If you leave your vehicle engine running unnecessarily, you can be fined £20.

Pollution enforcement officers can issue a £20 fixed penalty notice to drivers who refuse to turn off the engine of a vehicle running unnecessarily. This includes buses and taxis idling on stands. The driver of the vehicle has to pay this penalty, not the owner or company which operates the vehicle.

They will not penalise drivers in cases where common sense dictates that the engine needs to be running e.g.

• defrosting a windscreen for a short time on an icy day
• the vehicle has broken down and is being fixed