Spectre of Invasion: The Royal Navy and the Defence of Britain's Coast, 1900–1918

By Steve Dunn

“Dunn’s volume is well worth reading, and concludes that today Britain’s maritime shield has vanished, with unprotected coasts and sixty-two Royal Navy ships, one quarter of the number of US Coast Guard cutters.” – National Maritime Historical Society

By 1900, the British government and public had become gripped by a new and growing fear of invasion, not from traditional enemies such as France, but from Germany. Such terror was driven by lurid books and fanned by newspapers. These anxieties sparked off a fight between those who wanted a defence based on a larger standing army, with conscription to support it, and those who believed the Royal Navy was sufficient to defend the coast and deprecated the expense and role of a standing land force.

With war declared in 1914, Britain’s coastline came under attack. Major German raids created terror, and the fear of invasion drove naval and military planning and dispositions to protect Britain’s littoral. Coastal towns such as Scarborough, Great Yarmouth, Lowestoft, Southwold and even the Outer Hebrides came under attack and landings by German troops were feared daily. Running battles were fought with these attacking forces and both ships and lives ashore were lost. Spectre of Invasion examines all of the raids made and the success or failure of them, and relates these events from the point of view of naval and civilian participants. It tells the story of the Royal Navy and its role in the defence of the British coast in the First World War and examines the strategic and political developments resultant from invasion fears. And it considers how the plans laid for coastal defence fared under the test of conflict, laying bare what it was like to be part of the battles around the British coast, both as combatant and as citizen. Finally, it looks at Britain’s inability to co-ordinate naval and military effort throughout the War.

This is a thought-provoking book which combines a fast-paced narrative with fascinating insights into Britain’s predicament in the years leading up to, and through, the First World War. It will appeal to anyone interested in this era of the country’s history and the fear on invasion that stalked the country in those years.

• Language: English
• Publisher: Pen and Sword
• Release date: Aug 31, 2025
• ISBN: 9781399039925

Steve Dunn

Steve Dunn is an author with a special interest in the Royal Navy of the late nineteenth century and the First World War. He has written biographies and narrative histories, most recently Blockade and Securing the Narrow Sea, both published by Seaforth. Steve lives in Worcestershire and southwest France.

Book preview

Introduction

An island archipelago, Britain has ever been susceptible to invasion from the sea. The Roman and Norman ones are well known but there were many others, some invited, most not.

As a result, there has always been a clamour for coastal defence. Castles, fortified emplacements, redoubts and trenches were built from earliest times, with coastal artillery being added as it became available. During the French Revolutionary Wars, Martello towers dotted the landscape and many volunteer organisations, such as the Sea Fencibles, were formed to defend the littoral. Even the creation of Belgium in 1831 can be seen in terms of protecting the English Channel coastline and oceanic access.

In one of many French scares, a Royal Commission recommended the expenditure of £11.8 million on fixed defences between 1859 and 1863. Dover and Deal, Portsmouth and Plymouth still exhibit signs of all these historical works, as do scores of other locations. Despite this, in 1887, French Admiral Hyacinthe Aube advocated the bombardment of British coastal towns as a legitimate tactic in any war with the old enemy.

Quite who was accountable for coastal defence was a moveable feast. In 1771 it was decided that it was the Royal Navy which held the primary responsibility for preventing invasion and in the late nineteenth century, the RN was being described as ‘Britain’s Sure Shield in Peace and War’. By 1900, the reality was more complex. The Royal Artillery manned the fortifications, the Royal Engineers were responsible for the remotely-controlled mines and the Brennan torpedo harbour defence system, and the navy guarded the seaways.

However, it was becoming clear that technology was overtaking the existing methods of defence. Naval gunnery range and accuracy had increased considerably since Napoleonic times and the muzzle-loading rifled cannons mounted in the coastal fortifications were outranged and outweighed by the latest ships and weaponry. Moreover, existing plans did not take into account the risk of attack on British harbours by the recently developed torpedo boats and submarines.

Additionally, as the new century dawned there was a freshly-minted great fear of invasion, not from traditional enemies such as France, but from Germany, across the North Sea and increasingly bellicose. This terror was driven by books from authors such as Erskine Childers and H G Wells, and fanned by newspapers, especially Alfred Harmsworth’s Daily Mail. This rampant fright led to the Committee of Imperial Defence commissioning General John Owen to produce a report on the state of Britain’s land/sea defences, which was released in 1905. It proved to be damning and recommended an immediate upgrade in weaponry, based around breechloading 9.2in, 6in, 4.7in QF and 12pdr QF weapons. Coastal defence therefore became a battlefield for public money between the army and the navy, each wanting increased expenditure for more resources and in part using coastal defence to justify their positions.

At around the same time as Owen, First Sea Lord Sir John Fisher, naming Germany as the likely foe, and committed to reducing the cost of the navy, scrapped 150 outdated vessels and reorganised the fleets, concentrating his heavy ships in home waters and clustering the best and newest ships where they were well placed to protect Britain’s southern and eastern coasts. However, between 1905 and 1907, Fisher began to recognise the dangers to his heavy units posed by small torpedo-carrying craft operating in the North Sea, constricted and often shallow. Instead, he developed the theory of Flotilla Defence, whereby the battlefleet would not patrol in the North Sea but smaller vessels would take the responsibility. In 1912, the naval part of this system on the east coast came under the command of a newly created post, Admiral of Patrols, although the static guns were still manned by the Royal Garrison Artillery and the recently installed searchlights by the Royal Engineers. This was the position when war came in 1914.

With war declared, the Defence of the Realm Act gave government unprecedented dictatorial powers, which were especially exercised in coastal areas, controlling citizens’ movements, restricting access to beaches, prohibiting street lights, etc. In addition to naval and static defences, ports and harbours were now protected by the simple expedient of blockships, sunk in existing channels to deny access, such as the old HMS Hood at Portland, or ancient cargo vessels at Dover. Booms and nets were positioned across harbour mouths to prevent access except when opened.

Minefields and mining became a key part of coastal defence and the navy’s minelayers were out in all weathers laying new fields. Soon the whole of the eastern seaboard of Britain was a long continuous minefield with narrow gaps to allow egress and access, and a swept War Channel along the littoral was created which ran from Dover to the Firth of Forth.

The Royal Navy had nowhere near enough resources to deal with all the wartime tasks that now devolved to it. Motor pleasure craft were taken on to patrol harbours, steam yachts to monitor the seaways, and trawlers to sweep the path through minefields and operate boom defences.

But the system proved fallible. Major coastal raids were made by the German fleet on such east coast towns as Dover, Lowestoft, Great Yarmouth, Scarborough and Hartlepool; and to the west the Cumbrian coast and even St Kilda in the Hebrides were attacked. Running battles were fought with these attacking forces and both ships and lives ashore were lost. The coastal artillery was unsuccessful in driving off such raids; and the naval resources were overstretched. One reason was that so much naval capability, especially light cruisers and destroyers, was tied up with the battle fleet at Scapa Flow. Unforgivably, the site chosen as the fleet’s wartime home was completely undefended when war came. Admiral Jellicoe, commanding the Grand Fleet, had to improvise protection and use Royal Marines to man guns taken from warships and mounted ashore.

From the outset of war, the Royal Navy had been given the responsibility of protecting the coast and London from Zeppelin attack, another scare driven by the imagination of authors, such as Wells and his book War in the Air. Ill-equipped RNAS aircraft flew night sorties against the giant gas bags, and monitors were positioned in the Thames to shoot at them. The navy even took charge of the anti-aircraft guns ringed around London, a situation which lasted until 1916 when the army took back what should always have been its role.

Invasion fear reared its head again in 1916 and a squadron of predreadnought battleships was moved from Scapa Flow to Sheerness to add its guns to the defence of the south-east coast. They would have had a short life up against the German High Seas Fleet, but could have value fighting an invasion force.

Science was called in to help with coastal defence. The great physicist William Bragg Snr was recruited to work on underwater detection. Bragg loops, for detecting submarine movement near harbours, and (eventually) hydrophones were the fruits of his labours. The navy developed the Y-system of wireless listening posts along the east coast and a long line of acoustically magnifying giant ‘earphones’, manned by civilian volunteers. Both of these creations were intended to give warning of German Zeppelin and ship/submarine movements.

This book tells the story of the defence of the British coast from attack or invasion, primarily in the years leading up to, and during, the First World War. It is based on the particular perspective of the Royal Navy and the navy’s role, actions, successes and failures are detailed and examined. It is a tale little told and one of considerable interest now, as the world comes to terms with the fact that such assumed givens as security of food and energy supply, sanctity of borders and freedom of the seas, are not as inviolable as politicians would give us to believe. The first duty of government is surely to protect its citizens; maybe ministers should recognise this rather more than they seem to.

The narrative that follows is not necessarily in chronological order but rather structured by topic. Naval ranks are given as at the time of the actions described. The 24-hour clock is used throughout for clarity; where ante or post meridian was given in the original documents, the time has been converted. A date in brackets after the name of a ship is the year in which it was launched. In the period covered by the book, the War Office was responsible for the army and the Royal Flying Corps and the Admiralty for the navy and the Royal Naval Air Service. After 1 April 1918, when the air arms were merged, the War Office had responsibility for the combined force.

Finally, it may be useful to note that all Conservatives were Unionists but not all Unionists were Conservatives. Joseph Chamberlain and his Liberal Unionists were driven to combine forces with the Conservative party by Gladstone’s first Home Rule bill of 1886. Between 1895 and 1905 these two political entities ruled as a coalition, with Chamberlain joining Prime Minister Salisbury’s Cabinet. In 1912 the two wings of unionism formally merged as the Conservative and Unionist Party. The Liberal Party won the General Election of 1906 with an overwhelming majority. However, in the elections of 1910 they lost many seats and as a result were not the largest party in the House of Commons. They remained in power only through the support of the Irish Nationalists, backing given in exchange for an Irish Home Rule bill. This led to many on the right suggesting that they were not a legitimate government as they remained in power despite not having a parliamentary majority and refused to submit their key policy (Irish Home Rule) to the electorate.

1

This Precious Stone Set in the Silver Sea

So wrote William Shakespeare in 1590, putting the words in John of Gaunt’s mouth in his play Richard II, and going on to add that the waters around Britain were ‘a moat defensive’. An accident of tectonic plate movement, successive ice ages and the flooding effect of glacial meltwater had gifted Britain with a superb defensive wall. Once joined to Europe by a land bridge that linked the Weald in Kent to the Boulonnais in the Pas de Calais, Britain exited the Pleistocene as a group of islands surrounded on all sides by water.

But this sea-girt position was not only a protection, it was also a road, a route for invasion and settlement. The first invaders arrived in dribs and drabs, but in 55 BC the Romans and their legions came, crossing the Channel under Julius Caeser and establishing a client state which persisted until 43 AD when the Emperor Claudius staged a full-scale invasion, with subjugation of the local tribes (except those in Scotland) complete by the 80s.

However, Roman occupation did not bring safety from other aggressors; Picts, Franks, Scots and Saxons all troubled the shoreline and during the third century AD a series of forts sprang up along the southern littoral, under the overall command of ‘The Count of the Saxon Shore’, whose task it became to protect the coasts of Britain and Gaul from the attacks of the Saxon pirates and their like. Originally built with the control of shipping and trade in mind, these fortifications found greater use in the protection of Roman Britain from seaborne invasion by marauders from across the North Sea. The Saxon Shore Forts were placed at strategically important coastal inlets and estuaries, and safeguarded key Roman settlements, from the Wash in northern Norfolk round the east and south coast of England down to Portchester Castle in Hampshire (see Appendix 1).

But as Rome came under attack at home, soldiers and resources were withdrawn from Britain and by 401 AD most had been removed. The ocean road now facilitated Saxons, Jutes, Danes and Vikings to sail over the North Sea or down the English Channel and settle Albion’s pleasant shores, without as much let and hindrance as before. The invasion of Britain by multiple opportunists began; and as one wave of incomers established their power, it was challenged by the next wave of soi disant settlers. It became evident that to stop the newcomers, naval force might be an advantage.

Himself the product of a previous invasion, Alfred ‘the Great’ (King of Wessex from 871–c 886 and King of the Anglo-Saxons from c 886–899) saw the benefit of a fighting navy to protect against, or repel the incursions of, rampaging Norsemen. Around 896 he had ordered the construction of a flotilla of longships to his own design, all having sixty oars, which made them twice the size of the Viking longships and thus able to carry double the number of fighting men.1 He appreciated the doctrine of sea power and command of the sea. If enemy fleets could be intercepted before they landed, he might save his kingdom from despoliation. In practise his ships proved difficult to manoeuvre, but the tactical intent was important and served for future naval thought. Notwithstanding the unwieldiness of his ships, Alfred won important naval victories, perforce close to the littoral or in river estuaries, such as that of 896 when his nine new ships intercepted six Viking vessels and inflicted 120 casualties, at a loss of only half that number among his own forces. Unable to put out to sea through lack of manpower, the Norse ships were wrecked on the coast (possibly at Selsey Bill) and the survivors hanged at Winchester.

Another early monarch to recognise the benefit of a fighting sea force was also of Anglo-Saxon descent, King Edgar (ruled 959–975). At his coronation he allegedly summoned six client kings to Chester, including the King of the Scots and the King of Strathclyde, and made them pledge their word that they would be his liegemen on sea and land. Later chroniclers made the number of kings into eight and have them all plying the oars of Edgar’s state barge on the River Dee as an act of obeisance. With Edgar, the union of England under one dynasty became more firmly established. Highly conscious of the importance of sea power, the king was said to have built up a navy of 3,600 ships by the time of his death, which were deployed to guard England’s coasts from the incursions of the Danes. There will, of course, be an element of exaggeration in this account, but even if halved the number of ships he could call upon if necessary was formidable.

Indeed, defence of the coast by naval means seems to have been the default position in the time before the Norman Conquest. ‘The emphasis seems to be almost entirely naval. Edward the Confessor defends his people by sailing out from Sandwich every summer, and is appeased by a gift of a great gilded warship.’2

Then came, by sea of course, the Norman Conquest. The Normans’ goal was to acquire land and once it was gained they built castles to defend it. Despite being descendants of seafaring Vikings, after the conquest ‘is to enter a world dominated by cavalry and castle … indeed when ships were needed in 1066, they have to be borrowed or built from scratch’.3 And when William the Conqueror, now William I, was himself threatened by Danish invaders, instead of sailing to meet them, he despoiled the crops and fields inland from their likely landing places, so they would have nothing to live on. Despite this, the idea of seaborne defence did not die.

The Cinque Ports

One reason the concept did not fade was the creation of the Cinque Ports. From the Old French for ‘five harbours’, the Cinque Ports had their origins in the reign of Edward the Confessor (1043–66). In return for certain privileges, some south-eastern ports undertook to supply men and ships for the king. Hastings, New Romney, Hythe, Dover and Sandwich (later joined by the so-called Ancient Towns of Winchelsea and Rye) undertook to provide fifty-seven ships for 15 days’ service annually, each port taking a portion of the responsibilities. (For a summary of the benefits they obtained, see Appendix 2.)

If more than the defined term of service was requested, there was no obligation to provide it. ‘The aristocracy of the Cinque Ports were … bound to assist … but their obligations were not infinite … the Portsmen were required to turn out for only two weeks. The king might appeal … for longer, either in return for payment, or simply as favour, but his appeal might fall on deaf ears.’4 When the famously warlike King Edward I was battling Llywelyn ap Gruffudd for control of Wales in July 1277, ‘courtesy of the men of the Cinque Ports, Edward was able to dispatch some 2,000 soldiers across Conway Bay and the Menai Strait’5 to achieve a famous victory. The contribution of the Cinque Ports to naval defence would continue throughout the thirteenth and fourteenth centuries with their final naval service being to meet the threat of the Spanish Armada.

Naval Kings and Queens

Edward I was a ruler who understood the importance of sea power in the defence of his realm. Threatened with a French invasion in 1295, he created a great fleet; ‘his new galleys – fighting ships with 120 oars a piece – were now ready under the command of William Leybourne, who was duly accorded the newly coined title of Admiral of the Sea. They were backed up by teams of paid men patrolling the shoreline.’6

Richard I had granted the first charter for the town of Portsmouth in 1194. The fortifications that can still be identified in parts of the city have their origins in the fourteenth century. With England almost continually at war with France, Portsmouth bore the brunt, supposedly being burned down four times between 1338 and 1380. The result was to build walls around the city, shortly followed by the Round Tower, which could fire at enemy ships making their way up the Solent. Henry VII built the Square Tower, to further fortify the entrance to the Camber area, and constructed the dockyard. Henry VIII also helped design Southsea Castle.

Indeed, Henry VIII established a more formal naval force than had hitherto existed, the ‘Navy-Royal’, and was also responsible for the creation of the supporting anchorages and dockyards. He also built land fortifications to prevent foreign invasion, the so-called Device Forts, also known as Henrician Castles, a series of artillery fortifications constructed to defend the southern coast of England, the largest coastal defence programme since the Saxon Shore. The defences ranged from earthen bulwarks, through small blockhouses and artillery towers, to state-of-the-art fortifications influenced by the latest Italian designs. Henry took a personal interest in the military engineering techniques of the time, and approved and amended the designs himself.* They were ruinously expensive, costing £376,000 in 1546 money, much of it raised through the Dissolution of the Monasteries, for thirty castles, earthworks or blockhouses (see also Appendix 3).

By the late sixteenth century, the largest and richest empire in the world was that of Spain. British naval forces successfully played their part in repelling a Spanish attempt at invasion in 1588. A great Spanish fleet sailed from Lisbon in late May under the Duke of Medina Sidonia, with orders to sail up the English Channel, link up with the Duke of Parma in Flanders, and escort an invasion force that would land in England. The objective of the exercise was regime change: to overthrow Elizabeth I, reinstate Catholicism in England, end support for the Dutch Republic in its struggle with Spain, and prevent attacks by English and Dutch privateers on Spanish interests in the Americas.

But it was those very adventurers and privateers – men such as Frobisher, Drake and Raleigh – who led an English fleet which sailed from Plymouth to defend the nation. Faster and more manoeuvrable than the larger Spanish galleons, they were able to attack the Armada as it came up the Channel. Medina Sidonia was advised to anchor in the Solent and occupy the Isle of Wight but he refused to deviate from his instructions. Although the Armada reached Calais, while awaiting communication from Parma it was attacked at night by English fire ships and forced to scatter, and then suffered further at the Battle of Gravelines. Only a change in the wind saved the Spanish great ships from running aground, allowing them to escape into the North Sea. Pursued by the English, the Spanish ships returned home via Scotland and Ireland. Some eventually got home, but twenty-four ships were wrecked along the way. Aggressive naval assault of the type favoured in the past by Alfred the Great and Edward the Confessor had saved England from the ravages of Spanish landings.

From the Plantagenet age onwards, the cost of the ad hoc naval protection provided by the state was met (at least in theory) by the levy of ‘Ship Money’, a tax on the inhabitants of coastal areas of England and one of several taxes that English monarchs could raise by royal prerogative, without the approval of Parliament. Under the Plantagenets (ruled 1154– 1485), littoral towns and cities could commute the demand to supply ships and men in time of war or danger through the payment of a cash sum. Over time and in different reigns, this payment became an established tax, Ship Money, and an important source of income for the crown, whether or not it was spent on naval protection. As late as 1619, James I was able to extract £40,000 of Ship Money from London and £8,550 from other maritime towns. It was the attempt by Charles I, desperately short of money and reluctant to ask for more from Parliament, to levy Ship Money during peacetime from 1634 onwards, and to extend it to the inland counties of England without Parliamentary approval, which provoked a backlash from the monied middle class and became one of the key issues which fomented the Civil War. Only when his son Charles II came to the throne was the navy established on a proper basis and funded more from general taxation.

Indeed, Charles II was very naval minded, as was his brother, the future James II. Charles saw the need to protect sea borne commerce as a paramount mission for the navy. From early on in the restored monarchy the brothers publicly declared their determination to support and protect trade. Convoy was introduced in time of war, with merchant vessels escorted by the navy, and ships were stationed out in what came to be called the Western Approaches to meet and escort incoming merchantmen from the Mediterranean or the Atlantic. This is exactly the same problem and solution found by Admirals Lewis Bayly and Max Horton in the Western Approaches during the First and Second World Wars respectively.

The Seven Years War

In 1756 came a new war with France and Spain, a war fought for global domination as the French strove to emulate the Spanish and the British to stop them. Another invasion of England was planned and again the Royal Navy would prevent it. Bottled up by a close blockade of their coasts, the French finally attempted a breakout in late 1759: and Admiral Edward Hawke was waiting for them. In the Battle of Quiberon Bay, 20 November 1759, Hawke demolished the French invasion fleet off the coast at St Nazaire, which had consequences for Britain that surely compare favourably with all that Nelson would achieve later in the seas off Cadiz. Hawke destroyed six and captured one of the twenty-one ships that he faced. The invasion was abandoned, through magnificent British seamanship and bravery; and William Boyce and David Garrick wrote Heart of Oak in Hawke’s honour!*

The French Revolutionary and Napoleonic Wars

Invasion by, and conflict with, France once again threatened in the early nineteenth century. Between 1797 and 1815 Britain was held in constant dread of an incursion from France; indeed, one landing was made near Fishguard – by the ‘Black Legion’ – but was driven off by the locals. By 1803, Napoleon was assembling invasion fleets at Boulogne and Flushing. In response, Home Secretary Charles Philip Yorke passed a Defence of the Realm Act, which required all counties to submit a full report on all ablebodied men aged between 15 and 60, classifying those in the volunteer regiments, those willing to serve, to drive waggons or act as guides, as well as the details of waggons, boats, horses, cattle, food and forage. The task of these levies, which emulated the French levee en masse by raising a huge number of volunteers, was to harass and wear down the enemy if he landed. The French were to be denied the means of living off the land by the burning of all corn and other crops as they disembarked. Farmers would be given chits to indemnify them for losses, and these tickets would be redeemable once the war was over.

Fear of invasion was rampant and Thomas Hardy used this in his novel The Trumpet Major (1880), where the threat of foreign dominance permeates the work and one underlying theme is that of the defence of the realm. However, to be successful, France had to have command of the Channel and the Royal Navy denied her this boon, a feat sealed by Nelson’s destruction of a combined French and Spanish fleet at Trafalgar in 1805. Nonetheless and hurriedly, a large fort was built at Eastney Point and redoubts constructed at Eastbourne, Dymchurch and Harwich. The Royal Military Canal in Kent was created as a barrier to advancing French troops and the landscape suddenly became dotted with Martello towers.

These were small defensive forts, built across the British Empire, mainly in coastal locations. Up to 40ft high and set out on two floors, Martellos typically had a garrison of one officer and 15–25 men. Their round structure and thick walls of solid masonry made them resistant to the cannon fire of the time, while their height gave a good platform for a single heavy artillery piece, mounted on the flat roof and able to traverse and fire around a complete circle. Some had moats or other batteries and works attached for extra defence. A total of 103 Martello towers were built in England between 1804 and 1812, set at regular intervals along the coast from Seaford in Sussex to Aldeburgh, Suffolk. A few were also constructed in Scotland and Wales. Many towers remain today as a mute memorial to past invasion threats.

A cutaway drawing of a Martello tower. (Author's collection)

Belgium

It may seem odd to claim a foreign land as part of the defence of British coasts; but the ports of Ostend, Zeebrugge and Antwerp are so placed as to represent a clear and present danger to British trade and control of the English Channel and southern North Sea if held by a power inimical to British interests.

During the French Revolutionary Wars, all three were taken by France. At the conclusion of the conflict, the Congress of Vienna (1815) portioned out Europe, led by Britain, Austria, Prussia and Russia. They decided that the Netherlands and the Southern Netherlands (the latter approximating to modern-day Belgium) would become a united monarchy, the United Kingdom of the Netherlands, with the House of Orange-Nassau providing the king. This placed Ostend, Zeebrugge and Antwerp under control of this new polity, which Britain saw as the best option on the table at the time to protect her interests.

But this new creation lasted only 15 years, for the outbreak of the Belgian Revolution in 1830 led to the de facto secession of the southern part of the state, leaving a rump which refused to accept the split, and a minor civil war ensued. This situation was only rectified in 1839 when the Treaty of London was signed, fixing the border between the two states and guaranteeing Belgian independence and neutrality as the Kingdom of Belgium. The Treaty of London officially recognised the independent Kingdom of Belgium and the five great powers of Europe (Austria, France, Prussia, Russia and Britain) also pledged to guarantee Belgium’s neutrality. This was entirely what Britain wanted – with the three ports held by a neutral power, whose neutrality was guaranteed by the so-called Concert of Europe, Britain’s coastal defence was substantially reinforced.

In 1866, the French had held exploratory talks with Prussia as to the possibility of France acquiring Belgian and Luxembourg. On 25 July 1870, just after the Franco-Prussian War commenced, The Times broke the story. Britain immediately insisted on a double treaty, one with France and one with Prussia and the North German states, which obliged the British to intervene militarily if either combatant invaded Belgium. Parliament approved a bill to increase military and naval forces by 20,000 men at the same time. As Prime Minister William Gladstone said of the situation, ‘we have an interest in the independence of Belgium which is wider than that which we may have in the literal operation of the guarantee’.7 Disraeli made the same point; ‘It has always been held by the government of this country that it was for the interest of England that the countries on the European coast extending from Dunkirk to Ostend to the islands of the North Sea, should be possessed by free and flourishing communities … and should not be in the possession of a great military power.’8 When Germany invaded Belgium in 1914 and occupied the coast and harbours, Britain’s security was threatened, as the progress of the war demonstrated when Zeebrugge and Ostend became German U-boat bases.

France Again

In 1848, King Louis Philippe of France was forced to abdicate the throne. He tried to pass the crown to his nine-year-old grandson, also Philippe. The National Assembly of France initially planned to accept the youngster as king but a strongly opposed public opinion made that impossible. The exking fled to England, disguised as ‘Mr Smith’, and on 26 February, the Second Republic was proclaimed. Louis Napoleon Bonaparte, nephew to the great emperor himself, was elected president on 10 December 1848. Three years later, on 2 December 1851, he declared himself president for life and subsequently Emperor Napoleon III in 1852.

Britain was worried about anyone named Napoleon; and the more so because ‘the new Bonaparte had high ambition to remake Europe and extend French power around the world, to restore the glory of the first Napoleonic era. But before he did this, the French Navy had to neutralise Britain by exerting the maximum pressure on British home waters’.9

Stack Rock Fort near Milford Haven, photographed in the early 1920s. (Author’s collection)

The French ironclad La Gloire was the first ocean-going ironclad, launched in 1859. She was developed after the Crimean War in response to new developments of naval gun technology, which had resulted in rifled guns and explosive shells, giving increased destructive power against wooden ships. (Author’s collection)

The French upgraded and completed new defences at Cherbourg, a few hours steaming from Portsmouth, making the port its first battleship base in the Channel and an arsenal for a potential invasion of Britain. It was an obvious danger to British military planning and an overt threat to her sovereignty of the seas. Britain’s response included building new fortifications, such as the one at Stack Rock, off Milford Haven, which was constructed between 1850 and 1852 to offer increased protection to the Royal Dockyard at Pembroke. As built, it housed three 32pdrs as well as a 12pdr. The garrison comprised an officer and thirty men. Then, in 1859, the French Navy launched La Gloire, an armoured frigate capable of firing explosive shells.

Technological Change

British coastal defence batteries were largely dependent on the guns developed for the Royal Navy. Thus, as ships became better protected, the relationship between ships’ armour and the increasing gun power required to breach it also meant that existing coastal defence artillery became less effective. The coastal defence guns of 1840 were primarily the 24pdr and 32pdr smoothbore guns which had changed little from the Napoleonic Wars. The later development of 8in and 10in shell guns proved effective against wooden ships, particularly their rigging. However, the introduction of La Glorie, and the prospect of more armoured ships like her, meant that the old smoothbore guns were unable to penetrate the armour of new vessels.

HMS Warrior photographed off Plymouth, probably during the later 1860s. She appears to have her original short bowsprit, which was replaced in 1872–5. (US Navy History and Heritage Command NH 71191)

These developments triggered panic amongst the political and chattering classes in Britain and this in turn produced three immediate responses. Firstly, the launch of the Royal Navy’s iron-hulled warship, HMS Warrior, completed in 1861, secondly, the advent of rifled breech-loading cannons, designed and manufactured by the Armstrong Company,* and thirdly, a Royal Commission, under the chairmanship of Royal Engineer Major General Henry (‘Harry’) David Jones, was established in 1859 to inquire into the state of Britain’s defensive fortifications and protection for its dockyards and arsenals.

The 1859 Royal Commission

On 7 February the following year, the Commission’s report recommended a huge programme of fortification to defend the country’s arsenals and naval bases. The Commissioners concluded that the fleet, standing army and volunteer forces, even combined, did not provide sufficient defence against invasion. Furthermore, the coastline which they considered to be at risk, the 700 miles from the Humber to Penzance, could not feasibly be completely fortified and therefore they recommended that ‘the fortifications of this country should be confined to those points … whose possession would give him [the enemy] sure bases for operations’. A detailed plan and costing was produced for each location which required protection, resulting in a massive programme that would cost around £10 million (maybe a billion pounds in today’s money).

Coastal batteries were recommended, to provide protected positions for heavy artillery which would be able to engage enemy warships and troopships. In some places, for instance high on a cliff, the guns could be mounted in a barbette or open gun pit. Where close to the shoreline and could thus be engaged directly by enemy gunfire, each heavy gun was mounted in a casemate, a vaulted chamber with an embrasure for the gun which was pierced through an armoured shield. As being mounted in an enclosed space limited the traverse of the gun, casemates were arranged in a long, curved row in order that the guns of the battery could track the progress of a passing enemy ship, each weapon engaging it in turn. Some were completely circular, enabling defence on all sides. Other fortifications were uprated. Stack Rock, mentioned above, was one gaining sixteen 10in and seven 9in rifled muzzle-loaders.†

A newspaper etching from 1881 depicting external and internal views of Admiralty Pier Turret at Dover. (Author’s collection)

The largest coastal gun to be installed in Britain was the Admiralty Pier Turret at Dover. This was an enclosed armoured turret constructed in 1881 on the western breakwater of Dover