London's first hydrogen fuel cell black cabs have been awarded road legal status, and have celebrated by taking to the streets for the first time.

The taxis marked the announcement by travelling around London, dealing with rush hour traffic and visiting the Society of Motor Manufacturers and Traders (SMMT) headquarters and some of the capital's iconic landmarks.

London mayor Boris Johnson has said he wants to make Britain a leader in fuel cell technology, and aims to have a fleet of the hydrogen taxis on the city's fleet by the Olympics in 2012.

"These prototype zero-emission taxis are a shining example of British ingenuity, combining revolutionary fuel cell technology with an iconic design classic. This marks an important milestone in my goal to create a cleaner cab fleet, firstly through introduction of the first ever age limits moving towards zero-emission vehicles as they come to market."

The taxis are developed by a consortium which is led by Intelligent Energy, and includes London Taxis International and Lotus Engineering. They should offer a range of 250 miles between stops and are said to boast a quick refuelling time of around three to five minutes.

"The Fuel Cell Black Cabs are now road proven with thousands of miles of operation. Indeed, many people may have seen them as they have been driven around various parts of the UK, but we are now happy to formally announce their road legal status and that you will be seeing more of them in the coming months," said Dr. Henri Winand, chief executive of Intelligent Energy.