More than half of holidaymakers have been hit by car hire rip off

Last year British travellers forked out £475 million over the odds because of appalling car hire rip offs. In fact, over the years, half of us have fallen victim, and a fifth of people have been burned so badly that they say they'll never hire a car on holiday again.

A study by Travelsupermarket.com found that the most common rip off was being charged a small fortune for a tank of fuel. Some 15% of people have bee hit by this, at an average cost of £83.21.

Around 11% of people were also charged a fee because they didn't return the petrol tank full - at an average cost of £97.76. The third most common rip-off is a charge for driving further than you had initially agreed. The average excess mileage charge is £167.96. And in fourth place is outlandish charges for cleaning the car after it is returned - 9% of people have faced this, at an average cost of £80.41.

Top ten rip offs

1) Charged for a tank of fuel (agreed in advance) £83.21
2) Refuelling fee (not agreed in advance) £97.76
3) Excess mileage £167.96
4) Cleaning of vehicle £80.41
5) Personal insurance £160.36
6) Car upgrade £125.33
7) Excess reduction £168.65
8) Additional driver £132.54
9) Damage to vehicle £258.30
10) Child seat £159.13

These charges are not only excessive, but often people had no idea that they could be charged for these things when they took the car in the first place. Some 47% of people think that prices are not transparent enough, while three quarters think you need to be on your guard when you pick the car up - so you don't face unexpected costs later.

The charges are bad enough when you make a small infringement of the rules. If you have an accident, the rip offs can go through the roof.

Sally Irving from Birmingham was ripped off for thousands of pounds after having an accident in her hire car while she was in Italy. She says: "We had booked through an online broker and were returning our car to the actual rental company at Pisa airport when we hit another car. Although we paid the contracted excess charge of £850 at the airport's return desk, I came home to find they'd charged another £2,000 to my credit card without my permission."

She demanded proof that the repairs had cost quite so much, but the car hire company refused. She says: "Eventually, my credit card company refunded the money after I complained relentlessly in the months that followed. It was an unnecessarily stressful and potentially costly experience, especially considering we'd taken out the required excess policy – you don't expect to pay any more than that."

Protect yourself

It's hardly surprising that a fifth of people have been put off getting a hire car entirely. However, they can be incredibly useful. The study found that 36% of people value the freedom it gives them to go off the beaten track, while 26% say it's the easiest way to travel as a group.

It's therefore worth taking seven steps to protect yourself.

1. Book in advance
Bob Atkinson, TravelSupermarket's travel expert, says not only will you get a cheaper deal if you book as long as possible in advance, but you will also have a better choice of cars.

2. Book carefully
Some 71% of people in the survey say that rental is good value for money if you pay close attention when you book. This means checking whether you will need to bring the car back with a full tank of petrol, whether you will need to have it washed, and whether there is a limit on mileage.

3. Beware 'full-empty' fuel policy
It may seem handy to be able to pick the car up with a full tank and return it empty, but it will mean paying an inflated cost for fuel - and often paying for fuel you don't use. It's far better to find somewhere that will rent you a car with an agreement to bring it back with the same amount of fuel as when you left.

4. Check the small print for extras
If you need things like booster seats or sat nav, you need to bring them with you, because hiring them will mean paying a fortune for these extras.

5. Cover your excess
Hire cars are insured, but often with an enormous excess - of up to £2,000. Your best bet is to have this excess insured. The hire car company may offer you this - at a cost of around £20 a day. A far cheaper option is to get this extra cover before you travel - when it will cost around £3 a day.

6. Fight the hard sell
The study found that 18% of people had been pressured into an upgrade at the desk - sometimes by the hire car company claiming there were no cars left of the size you booked. In reality, you should be able to expect an upgrade at no cost - because it's up to them to provide the car you booked.

7. Don't pay in sterling
If you agree to pay in pounds, you will do so at a rate set by the company - and they are likely to set an uncompetitive rate - so you end up paying far more.