A leading high street bank is introducing new technology that will mean every credit card transaction is examined for fraudulent activity. The programme will affect 10 million credit card accounts and millions of transactions. But as a result, more legitimate transactions will be queried or even cancelled.

It is a fact that card fraud is on the up - it rose 15 per cent in the first half of the year and fraudulent transactions abroad now account for 40per cent of all credit card crime. It is not surprising therefore, that travellers are being advised to take several different payment methods when they go abroad such as cash, travellers' cheques and cards.

Banks previously checked around one quarter of all card transactions but the new system now means all card transactions will be screened in real time, with an acceptance decision made in a tiny fraction of a second. When you insert your card in a machine it now carries out an automatic check against your normal usage patterns and makes a decision about whether that transaction looks real or potentially fraudulent.

For a few years chip and pin technology was successful in reducing fraud but now professional fraudsters have worked a way round it, so card operators are now looking at more sophisticated means of combating the problem.

The problem is that as the banks become more proactive in targeting fraudsters, more legitimate transactions are being queried or declined. And it's not worth telling the bank you're going on holiday. As the whole process is automated, manual over-rides are excluded. This means that you're likely to have your card blocked as soon as you use it abroad.

But a spokesperson from the card issuers' trade body the APACS, said it was something consumers would have to accept. If people expect their banks to prevent fraud we have to expect that from time to time, we have to expect transactions to be periodically queried or card declined, especially abroad. That's a price the banks expect us to accept. So any transaction that is out of your ordinary pattern of expenditure can trigger the alarm bells at your bank.

A representative from ABTA, the travel agents' trade body, said that travellers cannot rely on their credit cards. Their advice is to take a range of payment methods when you go abroad. They suggest that you take cash for immediate expenses plus two cards, preferably from different banks. Then take some travellers' cheques as well for extra security if it goes wrong.

And if you have a mobile phone, take it abroad with you and put the customer care phone numbers for your credit cards into it before you leave. Then if a problem does arise, you may be able to sort it out without leaving the beach!

If you need the credit to finance your holiday, you can always pay for the cash and travellers cheques by credit card. You may be charged a service fee to this but it at least it means that you can have a good time and you can leave your credit card at home.