Holidaymakers heading off to Turkey have been warned to keep a close eye on their plastic after it was revealed as the worst country for overseas fraud on UK credit and debit cards.

Research by Barclaycard of foreign fraud hotspots puts Turkey top of the league although France, Spain and the United States are also high on the danger list.

These four countries accounted for more than half of all foreign fraud recorded by the company last year.

Sophisticated monitoring systems have helped to cut overseas fraud on UK cards by more than a third in the past four years, with losses falling from £138 million in 2001 to £83 million last year according to the Association for Payment Clearing Services (Apacs). But industry experts said that holidaymakers still needed to take care.

Sandra Quinn at Apacs said: "While industry initiatives such as chip and PIN have made the life of the international card thief more difficult, we must follow a few simple rules to make sure we are protected when on holiday. Simple things like using a concealed money belt to hide our cards and checking our statements carefully on our return can make all the difference."

Holidaymakers have also been warned to watch out for hidden fees charged by the card companies. Moneysupermaket, a comparison firm, reckons they could cost consumers £335 million this summer.

Most banks, building societies and credit card companies make a conversion charge -sometimes called a currency fee or loading charge -on all foreign transactions.

This can be as high as 2.75%, so a consumer spending £1,000 abroad could be charged £27.50.

Many companies also impose an additional charge on foreign cash-machine withdrawals.

Apacs has produced an online guide that offers advice to consumers travelling abroad this summer with their debit and credit cards.