How not to reduce your engine's efficiency

Driving with the aircon on when at low speeds means that you could be reducing your engine's efficiency by up to 20 per cent.

This means that your fuel bills will be creeping up. And nobody wants that.

This bank holiday, BP Target Neutral are advising drivers to switch the aircon off and wind the windows down, while crawling along at low speeds.

"Slowing down - Windows down should be the sensible motorist's mantra for this bank holiday weekend," says Andrea Abrahams from BP Target Neutral.

"If you're crawling along in a motorwat or A-road jam, or driving though town, turning off the aircon and letting the fresh air in naturally can have a big impact on your fuel consumption and CO2 emissions."