Toyota is contacting 1,900 UK Prius owners about a potential software problem that may cause the hybrid car to suddenly stall or shut down.

Toyota GB says that the fault may cause warning lights in the cars to illuminate, which then prompts the vehicle to revert to a fail safe mode.

The manufacturer is now contacting all affected owners by post but says that it is not a safety problem.

“This is not a safety recall, instead it is a special service campaign. The reprogramming work will be carried out free of charge and will take about an hour and a half to complete,” says a Toyota GB spokesperson.

Owners are assured that if the petrol engine stalls, the electric motor will have enough power to allow the driver to pull the vehicle over and away from traffic.

The software problem has also affected a further 160,000 Prius models in the United States and Japan. Toyota sold 1,588 models in the UK in 2004 and expects to sell more than 3,500 this year.