A survey by iCarhireinsurance.com compared the cost of a week’s car hire for 15 to 22 February from six European ski gateways (Barcelona, Turin, Grenoble, Geneva, Sofia and Innsbruck) from six international car hire companies: Avis, Enterprise, Budget, Europcar, Hertz and Sixt.

The average price to rent a car across all six destinations was £280, but when extras such as excess insurance, a ski rack, a sat nav and a child seat were added, the total jumped to £691 – two-and-a-half times the original price.

The most expensive place to hire a car was Geneva where the cost of one week’s car hire soared to more than £900 once extras at the rental desk were included.

The average price to hire a car in Geneva for a week in February was £447 but rocketed to £939 including add-ons.

Sofia was the cheapest for car rental. The average cost of a week’s hire was £84, with extras adding £304 to the bill.

Excess waiver insurance is one of the most expensive extras, adding £186 on average to a holidaymaker’s bill if it’s bought at the rental desk.

This will cover the driver for the excess that needs to be paid if the hire car is damaged or stolen.

However, it can be bought from specialist insurance companies, such as iCarhireinsurance.com, for £27.96 a week.

Ernesto Suarez, founder and chief executive of iCarhireinsurance.com, said: “It pays to ensure that you’re not on a slippery slope of extra costs when you pick up your hire car.   Research your car hire, as you would any aspect of your holiday, to identify ways to save money and keep costs to a minimum, such as buying an independent car hire excess insurance policy in advance of travel, avoiding putting multiple drivers on the contract, and bringing your own sat nav or using your smartphone to navigate.”