A new emissions free version of the iconic black cab has been unveiled in London today by the deputy mayor.

The prototype is said to look and drive just like a normal cab, but is powered by a hydrogen fuel cell system that only emits water vapour.

The vehicle is the result of a partnership between Intelligent Energy, London Taxis International, TRW Conekt and Lotus Engineering. It is reportedly capable of 80mph and has a 250 mile range.

London's deputy mayor, Kit Malthouse, said: "The black cab is a much loved London icon, but it is also a significant source of pollution especially in the centre of the city.

"This prototype Fuel Cell black cab, which emits only water from its tailpipe, is an exciting glimpse of how hydrogen technology could soon play a vital role in cleaning up air quality for urban dwellers."

Boris Johnson has committed London to making all taxis in the capital emissions free by 2020. A fleet of at least 20 Fuel Cell black cabs should be running by 2012.

Malthouse also confirmed that six hydrogen refueling stations – a key issue in the implication of fuel cell technology – were being developed across London.

The first of these will be used to refuel the five hydrogen-fuel cell buses due to be introduced to the capital's streets later this year.