London mayoral election: How has Sadiq Khan's Ulez and other green policies helped the capital?

Sadiq Khan likes to portray himself as the “greenest mayor ever”.

But how much of a difference has his flagship policy, the Ulez, made to air quality?

Has its controversial expansion to the Greater London boundary last August put his re-election in jeopardy?

And could the Silvertown tunnel opening in summer next year - and the linked tolling of the Blackwall tunnel - open up a new battle with the capital’s drivers?

Is the air cleaner?

In a word: yes. The London Air website, run by Imperial College, showed the capital covered in more than 50 red dots in 2016 — areas where pollution exceeded the recommended limits. By last year there were 12.

The Clean Air in London campaign group was so impressed it gave Mr Khan an A-rating for clean air in his second term — making him the first mayor to achieve the top score.

Transport for London’s target is to reduce roadside nitrogen dioxide by 60 to 70 per cent between 2016 and 2040.

By 2022 — prior to the Greater London Ulez — this had been reduced by 58 per