Radio Taxis Group cars will now run on E3, a biofuel produced especially for taxis and developed in partnership with UK fuel company Infinitum.
Blended using UK virgin oilstock, testing on the fuel found that it delivers a 7% reduction in CO2 emissions, as well as reductions in air quality emissions such as NOx, carbon monoxide and particulate matter.
There is also a 9.3% improvement in fuel economy.
The impact of CO2 emissions and improved economy means that the new fuel has the potential to deliver a fleet-wide cut of up to almost 3,000 tonnes of CO2 a year.
Speaking at the launch of the initiative, the Mayor of London Ken Livingstone said: “London already has the best taxi service in the world, and I am working with the taxi trade to make it the cleanest.
“New regulations introduced this year mean that the capital’s 20,000 black cabs must now meet strict emissions standards, to vehicles less polluting and help improve London’s air quality.
“I congratulate Radio Taxis’ commitment to go a step further and introduce a greener fuel in their vehicles. By tackling carbon emissions in this way, Radio Taxis is demonstrating that forward-thinking businesses have an important role to play in tackling climate change and I hope that other London businesses will follow their lead.”