Britons should not bank on getting the best bargains while visiting America, despite the weakness of the dollar against the pound, a survey out today showed.

Based on the total price of 10 essential items for tourists, the US was the most expensive of 15 countries surveyed by the Post Office.

Some items such as beer and suncream were four times more expensive in America than in other countries.

All told, the 10 items cost £69.41 in the US compared with £16.86 in Bulgaria which was the best-value country.

A bottle of beer was £3.15 in America but only 93p in Portugal, while a three-course evening meal for two was £52.58 in America but only £15.89 in Thailand.

The best-value long-haul country surveyed was South Africa, while Portugal offered the best value among the five eurozone countries surveyed, proving cheaper than France, Greece, Italy and Spain.

Post Office head of travel services Kevin McAdam said the holiday costs survey was a useful guide to pricing abroad.

But he warned: "You have to be careful when comparing costs in different countries. It all depends on their relative cost of living and it pays to be aware that favourable currency rates - like those currently available for the US dollar - do not necessarily mean a destination will be cheap.

"It's useful to compare the costs across Europe. Our survey proves that one currency does not mean one cost. With a difference of £32.25 between the shopping baskets in neighbouring Spain and Portugal, it is clear that there are savings to be made depending on where you choose to holiday in Europe."