Lotus is developing new technology to synthesise engine noise in hybrid and electric cars.

The move is to counteract concern that the virtually silent running of electric-powered vehicles is a risk to pedestrians, who cannot hear the cars approaching.

The manufacturer has developed a Safe & Sound Hybrid demonstrator, a Toyota Prius with a loudspeaker on the roof, which emits a noise depending on the speed of the vehicle.

Mike Kimberley, Lotus’s chief executive officer, said: “We hope legislators introduce minimum noise requirements for vehicles to encourage the adoption of technologies, such as ours, which will ultimately increase pedestrian safety.”