How hidden costs are adding £300 to the price of your holiday

But they might also like to have a stiff drink ready for when they see the bill.

The credit crunch, the soaring cost of oil and the weakness of the pound against the euro mean many Britons will face a raft of hidden charges for a few weeks in the sun this year.

These could add as much as £300 to the total cost for a family of four.

Smile now... Pay later... Families are likely to find a wealth of surcharges adding to the cost of their holidays

Some of the most swingeing increases come from airlines, which are struggling with the spiralling cost of aviation fuel.

Budget carrier Ryanair now charges parents £16 to have a baby or toddler sitting on their lap during the flight.

Thomson charges £29 for the same arrangement, as well as a £10 fee for travellers who want to be sure of sitting together on the plane. Other charges for checking in luggage, late bookings, in-flight meals and coach transfers all increase the final bill.

These small increases come on top of hefty fuel surcharges.

A typical family of four on a short-haul trip with British Airways could have to find an extra £128 on top of the ticket price this year - and the same group flying long-haul to the west coast of America could end up paying £872 more.

Banks have also been passing on the effect of the credit crunch to their customers.

Personal finance experts Moneyfacts.co.uk have identified 49 increases on major credit cards' fees and interest rates since last summer. This makes it more expensive to buy a meal, pay a hotel bill or hire a car abroad.

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HSBC said yesterday that from August 9 it is increasing the fee for withdrawing money from foreign cash machines with a debit card.

It will go up from 1.5 per cent to 2 per cent of the amount taken out, to a maximum charge of £5. The fall in the value of the pound against the euro means holidaymakers will find their money does not go as far this year.

Travellers to Europe will have to pay around 20 per cent more for everything from beer to ice cream.

Consequently, a family spending £800 on a holiday last year will now need an extra £160, while higher card fees, surcharges and hidden travel extras mean many will have to find a total of £300 extra.

The director of consumer policy at the price comparison service uSwitch.com, Ann Robinson, said: 'Families are in for a tough time this summer.

'With the miserable weather and the gloom of the credit crunch, it's not surprising that many are opting to flee the country for at least a week or two.

'But card fees, hidden surcharges and the high cost of the euro could put a real dampener on the holiday spirit. It's a lose-lose situation.'