Motorists are being warned not to leave their vehicles unattended while warming them up in the cold weather after three cars were stolen in Essex.
Police said in all three cases the cars had their engines on while owners were away inside their houses.
Officers are investigating whether the thefts, which took place between 7.20am and 7.50am on Wednesday, were planned and linked.
A spokesman said: "This isn't new, it's happened before in cold weather.
"Thieves notice that people turn their engines on to warm their cars up and then go inside for a cup of tea, or whatever. And then they simply get in the car and drive away."
A Ford Galaxy was stolen in Chelmsford and a Peugeot 407 and a Toyota Avensis were taken in Ingatestone.
Meanwhile similar thefts have taken place in Leicestershire. Last week a £33,000 Jaguar was stolen from outside a house in Markfield Road, Groby, as the owner waited for the windscreen to clear.
Also less than an hour earlier an £11,000 Ford Focus was stolen from a house in Narborough, and on Wednesday a £15,000 Focus was taken from outside a property on Timberwood Avenue, Groby.
© Press Association 2009