Conducted by CWC Environmental for Idling Action London, the research found that 78% of respondents usually or always switch off the engine when parked or pulled over. However, this leaves 22% of drivers who admit to regularly idling their engines.

Published today to coincide with National Clean Air Day, the study also revealed that 5-10% of drivers surveyed have stop-start technology, but have decided to disable it, with the most common reasons being that they worry it might wear out the battery or that they find it annoying.

Jointly led by City of London Corporation and Camden Council, Idling Action London is a Mayor of London Air Quality Fund project that saw 30 local authorities and City of London Corporation working together to tackle engine idling as a source of avoidable air pollution.

Nicholas Lyes of the RAC said: ‘Idling your engine wastes fuel, money and means you are unnecessarily emitting air pollutants. If your car has stop-start technology we strongly recommend you use it to help cut down on harmful emissions.

‘Drivers shouldn’t worry about start-stop as modern car batteries are designed to be switched on and off regularly and generally only engage the technology once the engine has been running for a while anyway.

‘Those with older cars without the technology should consider also manually switching their engines off when stationary for extended periods to help protect the health of those around them.’