Nearly a quarter (22 per cent) of UK drivers use their car boot as a permanent storage space, with one in 10 admitting to have never cleared out their luggage space. Carrying this extra weight affects fuel efficiency, meaning our cars use more fuel than necessary, according to research carried out by YouGov for Shell.

A third (32%) usually keep more than five items in the car boot. The top five currently on the roads of Britain are: tools (43%); wellington boots and outdoor clothing (27%); gym bag, sports equipment and golf clubs (11%); pushchair/baby equipment (9%) and multiple pairs of shoes (9%).

Three quarters of respondents said they would change the way they drive if it meant they could save fuel and reduce fuel costs.

Shell has launched a campaign to help a million motorists across the world learn how to save fuel. Called Target One Million, it employs a series of interactive, online mini-games to help drivers save fuel and reduce their motoring costs.

Quentin Willson, Shell’s FuelSave ambassador, said: “It’s amazing that so many of us are carrying around unnecessary items in our boots, meaning we’re wasting fuel and money every time we drive. The Target One Million mini-games are a fun and quick way for British drivers to learn how to drive more efficiently and reduce their fuel costs. Saving fuel can be really easy once you know how.”

The first mini-game – Shell FuelSave Challenge – is available now at www.shell.co.uk/targetonemillion . Players have the chance to win an iPad 3. More games will be released over the coming months.

As part of the research, Shell sent Willson to one of its forecourts to discover exactly what people keep in their boots: see what he found .