Link introduced the new rules in July following criticism from MPs. In its report on ATM fees released earlier this year, the Treasury Select committee said the current system of self-regulation was "totally inadequate" and was critical of Link, which currently regulates the UK's ATM network, saying there is no "comprehensive enforcement" of its rules on transparency.

The new rules require fee-charging ATMs to display the amount of the charge on the ATM screen before a card is inserted and customers must be asked to accept the charge before completing the transaction.

Units must also display standard-wording signs on the outside of surcharging machines, as well as on the screen informing the customer of the exact charge applied. Any signs directing cardholders towards a charging ATM must also say there will be a charge. ATM operators that fail to comply with the rules will be fined or disconnected from the Link network.

Link says a recent survey of 2000 fee-charging machines found that 13.2% did not comply with one or more of its transparency rules. Just over eight per cent of charging ATMs gave no indication on the body or casing of the machine that there would be a charge, and seven per cent of signs pointing to fee-charging machines did not say there would be a charge for use.

Link says the operators of these machines have been required to pay the penalties and in all cases operators have committed to bring non-compliant machines into line. Edwin Latter, Link card scheme director, says: "Link will revisit all none compliant machines early in the New Year and further sanctions will be applied for machines that remain non-compliant."

But Link says it is not aware of any evidence that the new standardised signage rules are insufficient to prevent cardholders from unwittingly incurring charges and has rejected a proposal put forward by the Nationwide Building Society and Halifax that would require ATMs to display green signs if they were free to use and red signs if they charged a fee.

Stuart Bernau, Nationwide executive director, says: "Current signage requirements are inadequate and the time has come for the industry to stop dragging its heels on this issue. Consumers deserve nothing less than clear, colour coded signs informing them whether or not they will be hit with a fee for withdrawing their own money. We are disappointed that the Link members have rejected the proposals for greater transparency."

Research commissioned by both Nationwide and Halifax indicates that UK cardholders are overwhelmingly in favour of colour coded signs on all ATMs to help them distinguish between free-to-use and fee charging machines. Over nine out of ten of those surveyed believed that green signs were a good idea.

But the survey also found that consumers are still confused about whether they will be charged a fee for making cash withdrawals at ATMs as a third of customers thought that machines displaying the Link sign were always free to use.

Almost 24,000 of the UK's 56,000 ATMs now charge customers for withdrawing cash.