By Jonathan Fildes
Science and technology reporter, BBC News
A "zero-emission" sports car with a top speed of nearly 100mph is set to be unveiled at the Geneva Motor Show.
The hydrogen-powered Lifecar, based on the design of the Morgan Aero-8 roadster, produces little noise and only water vapour from its exhaust.
The lightweight model packs advanced fuel cells and an energy storage system that gives the car a range of 250 miles (400km) per tank of hydrogen.
It has been developed by a consortium of UK companies and universities.
"Figures suggest the car should be capable of doing 0-60 [miles per hour] in about seven seconds," Matthew Parkin of classic sports car manufacturer Morgan told BBC News.
However, the exact acceleration will not be known until the complete car is taken for its first test drive.
"It's nearly there and the plan is to drive it when the show is over," said Mr Parkin.
The £1.9m project to build the Lifecar, part funded by the UK government, has taken nearly three years.
"The basic concept was to build an entertaining and fun sports car that would act as a showcase for the technology and would deliver 150 miles to the gallon," said Mr Parkin.
"Everything else has tumbled out from that."
The car is powered by a bank of lightweight hydrogen fuel-cells developed by UK defence firm Qinetiq.
"If you took a typical internal combustion engine and replaced it with a fuel cell, the fuel cell would be very large," explained Ian Whiting of Qinetiq. "That's not an efficient way to do things."
The fuel cells in the Lifecar produce about 22 kilowatts - roughly one fifth of the amount of power of a typical combustion engine.
"With that we can provide all of the cruise capability we need to," he said.
When the car needs to accelerate or climb a hill it draws extra power from a bank of ultra-capacitors aligned down the centre of the car.
"They are like a battery but they do not store quite as much energy and they allow the energy in and out much quicker," explained Mr Whiting.
These are primarily charged by a regenerative braking system which slows the car by converting the vehicle's kinetic energy into useful electrical energy using a motor.
"Hybrid cars already use regenerative braking - normally it restores about 10% of the energy," said Mr Parkin. "Lifecar is aiming for 50%."
The car has a range of about 250 miles (400km) and has a top speed of around 90mph (145km/h).
"The whole thing has to be built around efficiency which comes down to weight at the end of the day," explained Mr Parkin.
The seats are made of wood to keep the weight down
As a result, the car has an aluminium chassis and a lightweight wooden interior, including seats.
It also doesn't have any of the "luxuries" such as a stereo, central locking or even airbags, found on many modern cars.
"The objective is to get the weight down to 700kg."
There are also other notable omissions such as a gearbox and - as the fuels cells produce little noise - the roar of an engine.
"We may have to supply headphones with the sounds of a five litre V8 linked to the throttle pedal," said Mr Parkin.
Other car manufacturers have shown off hydrogen-powered sports cars, although many have been conversions of existing models or hybrid cars that can also run on petrol.
For example, Japanese manufacturer Mazda has unveiled a modified version of its RX-8, known as the Hydrogen RE, which uses a dual-fuel system.
Honda has also announced that its petrol hybrid CR-Z sports car concept would launch in 2009.
However, the road to a hydrogen-fuelled future has a number of obstacles.
Critics point out that to produce hydrogen by splitting water uses a large amount of electricity. At present, the majority of this electricity comes power stations burning fossil fuels and therefore brings no environmental benefit.
In addition, there is little infrastructure for refuelling the vehicles.
"There's a whole range of questions about how you [could roll out a hydrogen infrastructure] and when you could do that," said Mr Whiting.
"For vehicles which have a central base you can readily install a system to refuel those."
For example, hydrogen buses that return to a central depot already operate in many cities.
An infrastructure to refuel personal hydrogen vehicles would take longer, he said.
However, interim solutions do exist, such as so-called "reformer technology".
"It allows you to take the existing fuel infrastructure - diesel for instance - and convert it into hydrogen on the vehicle," said Mr Whiting.
The car is a concept at this stage but Morgan does not rule out going into production at some point in the future.
"We will gauge reaction when we show it," said Mr Parkin. "If there is an enormous response we will have to look at the project, the pricing and how it will function."
The car will be on display at the Geneva Motor Show in Switzerland between 6 and 16 March.
Other collaborators on the project were RiverSimple, Cranfield University, Oxford University and Linde AG.