A dozen airlines have been forced to stop ripping off their customers with hidden debit card fees for flights bought over the Internet.

The UK Office of Fair Trading (OFT) has told operators to put an end to ‘surprise’ surcharges that are not included in the original ticket prices.

From now on, the firms must include any debit card charges in the headline price instead of hitting customers at the end of their transaction

It follows an OFT investigation into some of Britain’s most popular holiday airlines, including Ryanair, easyJet, Lufthansa and Thomas Cook.

Officials spent 90 days looking into the airline charges after a campaign by consumer group Which?, supported by 50,000 people.

In the meantime, the airlines have agreed to abolish ‘hidden’ fees on debit cards and make credit card fees more transparent.

The other airlines pledging to change are Aer Lingus, BMI Baby, Eastern Airways, Flybe, German Wings, Jet2, Thomson and Wizz Air.

Clive Maxwell, the OFT’s chief executive, said: “This is a great outcome for the millions of people who buy flights online. It is important that the cost presented when they search for a flight is realistic and that they are not surprised by extra charges.”

Following the enforcement action, some of the airlines have already changed their practices. The rest will follow suit before the 1 August deadline – or face court action.

The OFT said people should not have to incur surcharges to use a debit card online as they are the “online equivalent of cash”.

However, it added that traders might still impose surcharges for credit cards, which can be more costly to process.

Sarah Brooks, director of financial services at Consumer Focus, added: ‘It is good news that there will be better transparency over card charges and consumers won’t have to endure hidden extras which bump up the advertised price.

‘Nothing is more frustrating for consumers than seeing a good online deal disappear on the final screen before booking.’

The UK government has announced it will bring forward plans for legislation to ban excessive card fees.

It is likely to cap credit card costs at a maximum of two per cent per transaction, or around 20p for a debit card payment.

Airlines regularly charge three or four per cent for credit card payments. Ryanair charges a £6 ‘admin fee’ per person per flight on most card payments over the Internet.

BMI Baby also charges fees per person per flight – £5 for credit card bookings and £3.50 for debit card bookings.

BA charges nothing for debit cards but imposes a £4.50 fee per credit card transaction.