Car thieves in Surrey have reacted to improvements in standards of vehicle alarms by breaking into homes to steal the car keys instead, police have said.
Police are warning people to keep their keys hidden from view
Surrey Police said there had been a spate of such incidents where high performance cars had been stolen in Spelthorne and Elmbridge this year.
Officers think sophisticated alarm systems have put car thieves off trying to actually break into the vehicles.
They have advised owners of valuable cars to keep their keys well hidden.
Poles through letterboxes
Surrey Police said there had been six occasions in Spelthorne and Elmbridge since the start of the year in which someone had broken into a house with a valuable car outside, taken the car keys and driven the car away.
Cars taken include BMWs, a Mercedes Benz, an Audi and a Ferrari.
A police spokesman said: "We are warning car owners, particularly those who drive high performance cars, that thieves have found a new way to steal the vehicles.
"Because car alarms and immobilisers are now so sophisticated they don't break into the vehicles any more, they steal the keys instead.
"In a number of cases keys hanging in hallways close to doors have also been stolen by thieves placing poles with handles or magnets on them through letter boxes to lift the keys down."
Police are advising car owners not to leave their car keys in obvious places in the house, possibly even locking the keys away.
They also advise extending house alarm systems to garages.