Boris Johnson dropped in to Potters Fields Park on Thursday to check out an exhibition of prototype zero-emission London taxis.
The Mayor of London has announced plans that would require all new taxis presented for licensing in the capital to be zero emission capable from 1 January 2018, with the expectation that they will automatically operate in zero emission mode while in areas where the capital's air quality is at its worst.
Mr Johnson met five manufacturers developing zero emission capable taxis – Frazer-Nash, Nissan, Karsan, London Taxi Company and Mercedes – several of whom displayed vehicles at the event.
The news follows a pledge the Mayor made last year to introduce an Ultra Low Emission Zone in central London by 2020.
"The London taxi is iconic in so many ways – not least in terms of its eye-catching looks and the way it is piloted by wily experts who know the capital like the back of their hand," said Mr Johnson.
"To date its one Achilles heel, particularly of older models, has been the pollution generated by chugging diesel engines.
"As part of my mission to improve our air quality and drive innovation, I'm making a firm pledge to Londoners that from 2018 all taxis presented for licensing should be zero emission capable.
"The cleaner, greener vehicles I've seen today are proof that the evolution of the great London cab is well and truly under way."