Riversimple Rasa is a super-efficient hydrogen car from Wales - pictures

The Rasa is a tiny two-seat hydrogen car from Welsh firm Riversimple.

With a carbon composite chassis and fibreglass body the Rasa weighs just 580kg.

The slippery bodywork has a drag co-efficient of just 0.224cd.

Prototypes of the Rasa are capable of a top speed of 60mph, which is achieved in 10 seconds.

At the end of the year, Riversimple plans to run a 12-month public trial with 20 vehicles.

Despite the high-tech drivetrain, Riversimple claims the Rasa will be available to lease for the same price as an entry-level Volkswagen Golf.

The Riversimple Rasa uses an 8.5kW hydrogen fuel cell - much smaller than the unit used in most other hydrogen vehicles.

The low weight and slippery body help the Rasa to achieve a claimed 250mph on the official urban test cycle.

The initial batch of vehicles will use a hydrogen refuelling station, but the location of this is 'yet to be announced'.

When the prototypes arrive we will find out if the Riversimple Rasa really can offer 'ultimate efficiency'.