Could this winter driving habit land motorists with a fine?

Consumer Editor

4 minute read|6th Nov 2026

Motorists trying to keep warm this winter could inadvertently fall foul of the law if they leave their car engine running unnecessarily while parked on a public road.

On a wintry morning, it is common for drivers to start the engine, turn the heater up and remain stationary for several minutes before setting off.

However, the rules on engine idling apply regardless of whether the driver is using the heating, waiting for someone, or simply sitting in the vehicle.

Rule 123 of the Highway Code states that drivers must not leave a vehicle's engine running unnecessarily while it is stationary on a public road.

The regulations state that a £20 fixed penalty can be issued for a stationary idling offence.

This means a police officer generally has to ask the motorist to switch the engine off first, with enforcement applying if they fail to comply.

However, drivers should be aware that penalties and enforcement arrangements can vary locally and for each country in Great Britain.

For example, the City of London Corporation currently states that the £20 Fixed Penalty Notice, can rise to £40 if it is not paid within 28 days, or an £80 Penalty Charge Notice, which can rise to £160 if it is not paid within 14 days.

There are also important exceptions that drivers should be aware of.

Keeping the engine running is permitted in certain circumstances, including when a vehicle is stationary because of traffic conditions, when the engine needs to run so a mechanical fault can be investigated, or if certain work is being carried out on the side of the road.

Drivers should also be aware of frost jacking. This is when opportunist thieves steal a car that has been left unlocked, unattended and with the engine running while it defrosts on a cold morning.

Drivers should stay with their vehicle while de-icing it, as insurers may also refuse to cover a theft if the car was left unattended with the engine running

RAC senior policy officer Rod Dennis said: “However tempting it might be to sit in a vehicle with the engine running and the heater on to warm up, we strongly advice against it.

“As well as polluting the air and wasting fuel, drivers who leave their engines idling unnecessarily on a public road also risk an on-the-spot fine of £80.

“On cold mornings, the best approach is to clear any ice or snow properly and ensure windows are fully demisted before setting off, then get on your way and let the car warm you up.”