Motorists should not leave their cars running unattended while attempting to warm them up on frosty mornings, warned AA Insurance Services.
Managing director Andrew Briscoe said: "Thieves look for cars left running on cold mornings, so warming your car in this way is an open invitation for the car to be stolen."
Briscoe said theft of car keys was becoming a great problem due to security systems, immobilisers and locks becoming increasingly sophisticated. This leaves taking keys as the easiest way to steal cars.
"Most car insurance policies will not cover theft of your car if it has been left unlocked and with the keys in the ignition," said Briscoe.
"Leaving the engine running to warm the car up while you go back indoors to warm yourself up with a cup of tea is taking a huge risk, yet it's surprising how many people do it."
