The question of whether credit card companies are responsible for purchases made abroad will be the subject of a High Court legal action starting today.

Products or services bought on a card in the UK are covered by legal safeguards that mean customers can claim directly against their credit card company if problems occur.

But a grey area exists over whether the same law applies to purchases made overseas.

The Office of Fair Trading (OFT) believes the safeguards apply to credit card transactions anywhere in the world.

But this is being challenged by three banking organisations, Lloyds TSB, Tesco Personal Finance (part of the Royal Bank of Scotland), and American Express Services Europe.

The OFT has asked the High Court in London to make a ruling on a point of law to clarify the situation.

Section 75 of the Act states that card issuers have "equal liability" with the firm selling the product or service if something goes wrong and the customer makes a valid claim.

The law only applies if the purchase is more than £100 and no more than £30,000.

The case is due to be heard by Mrs Justice Gloster and is expected to last until July 29. Judgement is likely to be delivered at a later date.