Jaguar is to fit its adaptive restraint technology system (ARTS) to 2001 model year XK series coupes and convertibles - but not increase prices.

Ultrasonic sensors monitor the position and weight of the front passenger and measure the distance of the driver from the steering wheel.

A Jaguar spokesman said: "ARTS greatly reduces the risk of airbag-related injuries caused by inappropriate deployments."

He said it would avoid repair costs and inconvenience which followed passenger airbag activation when the seat was unoccupied.

Jonathan Browning, Jaguar managing director, said: "We are a company in transformation with innovative models driving us to worldwide sales success. Enhancements to the XK and XJ series make them exceptional value."