Drivers could lose hundreds of pounds thanks to gaps in car insurance, new research claims.
Many insurers won't pay out for common incidents such as misfuelling, mobile phone damage or lost keys, according to data from Which?.
It analysed 73 elements of car insurance across 39 policies and found certain problems encountered by many drivers are not covered by a significant number of policies.
Despite all car insurance policies boasting personal belongings cover, 46 per cent don't cover mobile phones if damaged or destroyed in your car.
Many car insurers won't pay out for common incidents such as misfuelling, research found
A further 18 per cent of policies also excluded laptops and tablets, while only two of the 39 policies cover cash.
Meanwhile, 150,000 Britons pour the wrong type of fuel into their car each year – an accident that can lead to expensive engine damage, according to the RAC.
However, only 54 per cent of the policies Which? analysed provide mis-fuelling cover as standard, while 36 per cent don't offer mis-fuelling cover at all.
Of the policies compared, 18 per cent of insurers either only pay for draining the fuel from the tank or for repairing a damaged engine that's been run on the wrong fuel.
Only 28 per cent of policies automatically cover both.
While car insurance usually covers the costs of getting to your destination or back home if your vehicle breaks down, onward travel didn't feature in 26 per cent of policies, leaving motorists with a potentially pricey trip in a taxi.
Which? also found that many drivers with smashed sunroofs will find themselves unable to claim under the 'glass' section of their cover.
Glass cover is the part of the policy specifically related to the windscreen and windows, and it usually also includes sunroofs – but this was excluded in 18 per cent of policies.
If you lose your car keys most policies will have you covered, but there can be a catch – some 15 per cent will pay for replacement keys and locks – but not for the locksmith's call-out charges.
Just 46% of insurers don't cover mobile phones if damaged or destroyed in a drivers car
Meanwhile, another 15 per cent don't provide any cover at all for lost keys, instead only covering stolen keys.
To find the providers that can be relied upon to deliver both quality of service and cover, Which? surveyed more than 2,300 policyholders who have made a car insurance claim in the past two years.
It asked them how satisfied they were with their provider and how likely they would be to recommend it. It also analysed the standard policy of each firm rated.
Of the 16 firms receiving both a 'Customer Score' and a 'Policy Score', LV topped the table with customers praising the insurer's policy clarity, ease of online services and value for money.
It also achieved a four-star rating dealing with queries. Its 'total score', which is the average of its customer and policy scores, was 79 per cent.
Other top performers included NFU Mutual, Saga and Direct Line which had total scores of 78 per cent, 74 per cent and 73 per cent respectively.
Ageas, Admiral, RAC and Tesco Bank meanwhile achieved the lowest total scores.
Jenny Ross, Which? Money editor, said: 'When things go wrong drivers should be able to count on their insurer, but it is concerning that a large number of policies don't cover incidents or possessions you might assume they do, leaving customers with potentially eye-watering bills.
'We would urge policyholders to read the small print. If you're comparing two similarly priced policies, the bills you can rack up by falling foul of car insurance potholes could dwarf the extra amount you would pay for the more expensive cover.
'It's always worth shopping around when it's time to renew, but that's especially true for anyone who's unhappy with how their insurer has handled a claim.'
In December 2020, Which? analysed 39 standard and non-standard policies from 32 car insurance companies. In November and December 2020, Which? surveyed 2,361 policyholders and 2,736 people who had made a claim in the past two years.