This may be a tempting idea to stop drivers becoming cold while behind the wheel but can lead to vehicles being stolen in a major fraud.
Over three and a half million pounds of stolen cars were detected by Tracker between November 2019 and January 2020 which have been described as the peak months.
Clive Wain, Head of Police Liaison at Tracker said leaving a car running makes it an “easy target” for a crime.
He warned that drivers may find their insurance company refuses to pay out for any damages as this will be considered an at-fault claim.
He said that drivers were “inviting criminals” to enter a car every time they left an engine on unattended.
He said: “Whilst it is tempting to leave your car running with the keys in the ignition whilst unattended on frosty cold mornings, experience tells us it’s not a wise move.
“Not only does it make your car an easy target for opportunistic thieves, few insurers will pay out if you haven’t taken reasonable care to prevent your car from being stolen.
“It is also an offence under the Road Traffic Act, termed as ‘quitting’.
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“Frost-jacking is when your vehicle is stolen in the minutes the car engine is on to defrost or warm up the car, and the car is left unattended.
“It could be frost-jacked when you are getting ready for work, popping into a shop or dropping the kids into school, with or without keys or a car fob.
“Whenever you leave your car engine on, unattended, you are inviting criminals to take your car from you.”
Tracker warns that the first frost of the year could come as soon as November 11 making this the first target day for thieves.
However, with the darkness drawing in and heavy rain predicted for most of this week there is nothing stopping similar offences happening more quickly.
Tracker revealed that motorists can no longer be complacent about their car security after a shocking increase in crime over the past year.
Data from the RC has revealed that 150,000 cars were stolen across the UK between 2018 and 2019.
This was up by 10,000 vehicles on the previous year and up by a massive 5,000 compared with four years previous.