London mayor Boris Johnson has announced that the world’s first fully electric double-decker bus will enter passenger service in October, as part of the transport authority’s aim to reduce air pollution levels in the UK’s capital city.

The announcement was made as part of the world-first Clean Bus Summit, where the mayor also committed, with 24 other cities across the globe, to more than 40,000 ultra-low emission buses by 2020.

The trial of the new zero-emission electric double-deck buses built by Chinese manufacturer BYD will be carried out on Route 16 between Cricklewood and Victoria Station.

"The iconic red double-decker bus is about to become greener than ever."

Transport for London (TfL) has worked with BYD and used its latest cutting-edge technology to bring the world’s first purpose-built, purely electric, double-decker bus.

The summit was also attended by bus manufacturers, including BYD, Volvo, Wright Bus, Optare Mercedes Evo Bus and Alexander Dennis, and they committed to supporting cities in delivering fleets of new ultra-low emission buses.

TfL currently already has 1,300 hybrid electric and diesel buses in service, and since 2008, more than 1,400 buses have been retrofitted to reduce their emissions by up to 88%.

Mayor also noted that 800 new Routemasters will be on the streets by 2016 and are expected to reduce CO2 emissions by 27,500t annually.

Additionally, two Irizar-manufactured single-deck electric buses will also be entering into service in London shortly, which will join the eight single-deck electric buses built by Optare and BYD. The single-deck buses have been in service since 2013.

Johnson noted: "The iconic red double-decker bus is about to become greener than ever.

"London is a world leader in clean buses but we can’t do it alone, and events like this Clean Bus Summit are key to making further progress."

The mayor told that all new busses joining the central London fleet were compliant with tighter regulations on emissions within Ultra Low Emission Zones (ULEZ).

TfL aims to have 300 single-deck buses to be zero emission models by 2020, with all 3,300 double deck buses at least meeting the Euro VI electric hybrid standard.

Johnson noted that procurement of new buses should be initiated immediately in order for there to be enough buses in the fleet to meet these requirements by 2020.