British motorists hiring cars abroad are being urged to photograph vehicles before returning them following a 30 per cent rise in customer complaints.
The UK European Consumer Centre (UK ECC) received nearly 100 complaints in the first five months of this year, significantly higher than the same period in 2009.
The reports range from being wrongly charged for mysterious bumps and scratches, petrol and even missing seats.
The car hire industry says these complaints represent "a very small proportion of the 55 to 60 million rental transactions that take place annually" across the EU.
However as the UK ECC is not very well known, it believes that the number of complaints it receives represents only a small minority of cases.
Credit card charge
John Griffiths from Poole in Dorset hired a car last year whilst on holiday in Ireland.
A couple of weeks after he returned home he received a letter from the car hire firm informing him that the sum of 450 euro had been charged to his credit card for damage to the rear bumper of his hire car.
The damage had been identified in the pre-rental inspection so John Griffiths immediately contacted the company to dispute the charge.
"I was absolutely astounded and in fact very angry. I think it's incredible that they have the right to take money from my credit card without my authorisation."
As is common in many of these cases, John had an early flight so when he dropped off the car the rental office was shut and there was no member of staff to inspect the car.
His money was eventually refunded following the intervention of the UK ECC but many holiday-makers are not so lucky.
Tip of the iceberg
Jed Mayatt, manager of the UK European Consumer Centre said: "We knew that complaints about car hire were rising, but when we analysed our database I was really shocked at the scale of the problem."
Based on historical trends, the UKECC expects the number of disputes to rise to 400 by the end of the year. Complaints to the UKECC are believed to be the tip of the iceberg with many disputes going unreported.
The majority of its cases relate to car hire problems in Spain, Italy, France and Ireland.
Customers reported a range of hidden charges, including the cost of refuelling when the car had been returned with a full tank of petrol, extra insurance premiums and some holiday-makers paid for cars online yet on collection discovered their booking does not exist.
Jed Mayatt from UKECC commented: "Of course, not all car hires end in tears, but consumers really do need to wise up and take some basic precautions when they are entering into car rental contracts in the EU.
"Consumers are often at their most vulnerable during tough economic times and, quite naturally, they often have their guard down and are more trusting when they are on holiday".
"Our general advice to consumers hiring cars abroad is, where possible, to return the car to someone in the office, get them to check the car and sign it off as in good condition. If you have to leave the car, take some photos - showing that it was returned in good condition."
In a statement Leaseurope - which represents car rental companies across the EU - told 5 live Investigates that the number of complaints represented a "very small proportion of the 55 to 60 million rental transactions that take place annually".
Leaseurope says its members are "working with the European Commission and consumer centres across Europe to further enhance the industry's handling of complaints".
"We are currently piloting a European car rental conciliation service to handle this type of issue."