The world’s first hydrogen-powered double-decker bus will be trialled in London next year as London Mayor Sadiq Khan committed to phasing out “dirty” pure diesel buses.

Mr Khan yesterday announced no more pure diesel buses would be added to Transport for London’s (TfL) fleet from 2018.

And all new single-decker buses for central London will be zero-emission from today.

New York, Los Angeles, San Francisco, Amsterdam, Copenhagen and Cape Town are among 11 major cities which have agreed to phase out pure diesel buses by the end of 2020.

Paris, Madrid and Mexico City have committed to removing diesel buses from their cities by 2025.

Mr Khan said: “I want London to become a world leader in hydrogen and electric bus technology.

“I’m implementing hard-hitting measures to clean-up London’s toxic air and it’s great that more cities are getting on board to phase out the procurement of pure diesel buses which sends a clear signal that only the cleanest technologies are wanted in our cities.

“Transforming London’s bus fleet by accelerating the introduction of zero-emission buses is important and I plan to work with bus manufacturers, other cities, the European Commission and the C40 climate change leadership group of cities to move this agenda forward.”

It is estimated that the equivalent of 9,400 premature deaths occur each year in London due to illnesses caused by long-term exposure to air pollution, the Mayor’s office said.