A new zero-emissions taxi keeps a familiar shape, and could hit the road before the next Olympics. Details inside.

A new hydrogen and electric hybrid vehicle has been introduced to the streets of London, but it is by no means an unfamiliar site.  The Fuel Cell Hybrid London black cab keeps the iconic vehicle's shape, while maintaining a total range of 250 miles.

The car uses a combination of a fuel cell, powered by a tank of hydrogen, and lithium polymer batteries.  It is able to reach a top speed of 80 mph, and can be fully refueled in roughly five minutes.

"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," said London Deputy Mayor for Policing Kit Malthouse.  "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."

The base vehicle for the car is the LTI TX4, which has enough room for the hybrid powertrain without breaching the cabin or luggage space.  Engineers working for UK firms LTI Vehicles, fuel cell provider Intelligent Energy, automotive consultancy TRW Conekt and sports car manufacturer Lotus showed the car off at London's city hall this week.  The consortium hopes to raise additional financing to build a fleet of the hybrid fuel cell taxis in time for the 2012 Olympics.

Gallery: Hydrogen powered London taxi ready for launch in 2012