Chinese President Xi Jinping (C) is accompanied by his wife Peng Liyuan (L) and Britain's Prince William (2nd R) and Catherine, Duchess of Cambridge as they get off a showcase BYD electric bus at Lancaster House in London, Britain Octo 21, 2015.[Photo/Agencies]

President Xi Jinping and his wife Peng Liyuan on Wednesday hopped aboard the world's first all-electric, zero emission double decker bus, developed by China's clean energy auto company BYD.

Londoners will soon be riding on the new buses, according to BYD's founding chairman, Wang Chuanfu, who attended a launch ceremony along with the visiting president and Britain's Duke and Duchess of Cambridge.

Wang and Colin Robertson, CEO of UK coach and bus manufacturer Alexander Dennis Ltd (ADL), announced a major strengthening of their electric bus building partnership which has the potential to generate two billion pounds of sales for the two companies over the next 10 years.

"This event today really underlines that the era of electric buses has truly arrived," said Isbrand Ho, managing director of BYD Europe.

"At BYD we have proven battery electric technology, as demonstrated in our new double decker," he said. "In ADL we have an outstanding and experienced bus building partner. Together we can supply bus operators with the products they need."

The new bus will carry 81 passengers and is fully air-conditioned. It will be able to complete up to 190 miles in city traffic conditions on a single charge, allowing a four-hour recharge to be made at cheap off-peak electricity rates.

London's 9,000-strong bus fleet carries 6.5 million passengers a day, more demanding than those of Paris and New York combined. Two pure electric BYD single deckers have been in successful trial service with Go-Ahead on two Transport ForLondon (TfL) routes for almost two years. BYD recently secured an order for a further 51 single decker electric buses for operation by Go-Ahead.