A hush-hush £4 million research project by a Sussex engineering firm today received one of the highest accolades in the car industry.

The RAC has presented its coveted Dewar Trophy to Ricardo, which employs 1,400 people, many at its works on the banks of the River Adur in Shoreham.

The award was presented for the development of the company's i-MoGen hybrid vehicle, which is now being demonstrated to the world's leading vehicle manufacturers.

It called the project, based on a Vauxhall Astra with a diesel-electric powertrain, the most outstanding British technical achievement in the automotive field in 2002.

The RAC singled out the ability of i-MoGen - intelligent Motor Generator - to achieve average fuel consumption of up to 70 mpg combined with exhaust emissions 50 per cent lower than proposed Euro 4 levels as being "particularly relevant to the changing face of motoring."

Ricardo's founder was Sir Harry Ricardo, who was born and brought up in Shoreham.

During the First World War he was involved in secret government work with engines for the original British Army tanks and in 1919 he set up the Shoreham establishment.

Stephen Hammerton, RAC Motoring Committee chairman, said: "The Dewar Trophy has been a celebration of British technological achievement since it was first awarded in 1906 and Ricardo has shown it is well on the way to accommodating the needs of tomorrow's motorists.

"To develop a powertrain that combines such excellent fuel economy and low emissions that can be installed in Europe's most popular size of vehicle and comfortably accelerate to 100km/h in 12 seconds is an impressive feat.

"We also commended the fact that it can be manufactured at a cost that makes full-scale production a real possibility rather than a dream."

Neville Jackson, Ricardo technology director, said: "We are delighted to receive this additional recognition that the investment in Ricardo's biggest-ever research and development programme was money well spent."

Previous winners of the award include Girling for its anti-lock braking system and Dunlop for its fail-safe tyre.