If you are in the habit of running out in the morning to switch on your car to warm it up and defrost your windscreens, and then run back inside to finish your breakfast, your car is unattended and therefore Not Insured.
If your car is stolen while sitting there, warming up with the engine ticking over, the insurance company will not pay out on your claim. In order for an insurance company to pay out on a claim, there must be evidence of forcible entry or exit. Obviously, a car sitting there with its engine running is an easy target, and the burglar will have nothing to do except jump in and drive off.
So do pass this warning along.