This week we speak to British property entrepreneur and philanthropist Sir Jack Petchey. "Standing at the wrong end of a machine gun I imagined that I might be imprisoned, or worse," Sir Jack Petchey says. In a career that has spanned more than seven decades and taken him from ownership of a single taxi to the helm of a property business now worth a reported £550m, the entrepreneur says his arrest in Portugal was his lowest moment. It was 1974 and he was in the middle of building a holiday complex in the Algarve when there was a military coup. There was a lot of suspicion of foreign investors, he says, and this was evident when he found himself in court at 1am, accused of breaching rules on foreign currency. "Luckily I held my nerve, was released on bail and after two years the case was dismissed," he says. 'I knew we weren't rich' By that point he was well on his way to amassing his fortune, although he started life in much humbler circumstances. Born in 1925, Sir Jack's early years were spent in Manor Park in East London in a one-roomed flat with an outside toilet. The family's tin bath hung on the fence outside and was brought in every Friday evening for bathtime. Sir Jack's clearest memories of his childhood are of having fun. "We played out on the street, knocking on neighbours' doors and running away, or sticking coins to the pavement and watching as people tried to pick them up. "We didn't think of ourselves as poor, but I knew we weren't rich!" Despite being an advocate for education today, Sir Jack had no interest in school and left at 13, getting a job as an office boy soon after. After war broke out in 1939 he was keen to join the action and he volunteered for the Royal Navy when he turned 17. Sir Jack as a young naval cadet He was chosen for officer training, but failed to get through the selection process. What rankled was that an Eton-educated man passed, even though in Sir Jack's opinion he lacked leadership skills and had to be protected from being bullied. This experience only made Sir Jack all the more determined to succeed, a quality he says has been key to his success in life. He was transferred to the Fleet Air Arm and ended up as an aircraft engineer, servicing the planes that provided air cover during the Normandy landings of June 1944. Once he was discharged from military service, he went back to his pre-war office job, but found himself bored after the "excitement of the services". And it was another knockback that spurred him to move on. "I was ambitious, so I asked to be trained as a manager. But the personnel officer informed me I was not 'management material'." Outraged, he handed in his notice, but he knew he still had to pay his way - not least the rent and housekeeping money he owed his mother. So he put his discharge pay of £48 and his life savings together, bought a second-hand car and started a taxi service, picking up returning servicemen from the London docks. Sir Jack's first car hire office in East London Eventually he acquired another car and then an office, from which he started a car hire company in 1948. "Then I realised that selling cars was more profitable," he says. "So I bought a car showroom, and it wasn't too long before I realised that selling the car showroom was actually more profitable." Sir Jack (centre) opening the first Petchey car showroom in East Ham That was the start of a career in property, which was characterised by Sir Jack's willingness to seize opportunities even if it meant taking risks. After a close shave with bankruptcy in 1974, when property values crashed, he became a pioneer of the European timeshare movement, in which people buy stakes in holiday properties that they can only use at certain times of year. He introduced the concept to his own holiday complex in the Algarve in the 1980s and pursued timeshare projects in the UK too, where he had to defend them from some criticism. Not all of his ventures went smoothly though. He bought Watford football club