Announced at Mansion House last night, the proposal comes less than six months after the European Commission launched legal proceedings against the UK government for failing to meet 2010 NO2 limits and for illegal levels of harmful pollution in 16 areas of the UK.

So the Mayor is proposing widespread support of ultra-low emission vehicles, which include plug-in hybrid and fully electric cars, but could also include hydrogen fuel cell vehicles and the most efficient hybrids by 2020.

The manifesto sets out plans for 35 electric vehicle charging hubs across the capital, each with 10 charging points and wireless charging capability, as well as calling on additional government incentives for ultra-low emission vehicles.

To further reduce harmful emissions, the Mayor wants to London fleets to adopt 200,000 ultra-low emission cars, as well as 7,000 taxis, 11,500 private hire vehicles, 1,600 buses with a plug-in hybrid or fully electric drivetrain, and to deploy 350 electric vehicles in public fleets.

The manifesto also sets out plans for an Ultra-Low Emission Zone in central London, with a fee equivalent to double the Congestion Charge for diesels which don’t meet the 2015 Euro 6 emissions standards, and petrols which don’t meet Euro 4, which came into force in 2006.

The Mayor of London, Boris Johnson, said: ‘Improving London’s air quality is an urgent challenge, it affects the health and well-being of all Londoners, and it simply cannot be put on hold. Here at City Hall we are doing everything in our power to address it.

‘At the heart of this are my plans for the world’s first Ultra Low Emission Zone in central London from 2020. This will be a game changer, but with just a little more energy, ambition and action from Westminster and from Brussels, London can meet the EU limits for NO2 by 2020. It is possible, and together we can make it happen.’