Twelve airlines including Ryanair have agreed to include debit card surcharges in their headline prices following action by the Office of Fair Trading.

Aer Lingus, BMIbaby, Eastern Airways, easyJet, Flybe, German Wings, Jet2, Lufthansa, Ryanair, Thomas Cook, Thomson and Wizz Air were subject to an OFT consumer law investigation and have agreed to change their practices.

Eastern Airways, EasyJet, Flybe, German Wings, Lufthansa, Thomas Cook, Thomson and Wizz Air have already made changes to their pricing structures, websites and marketing materials agreed during the course of the OFT investigation.

Other airlines will change their advertising practices by August 1 and fully complete further changes over the coming months.

The carriers also agreed to make surcharges for credit cards more transparent so that these charges will be clearer and easier to find during the booking process,

The OFT estimates that debit and credit card surcharging in the airline sector cost consumers £300 million a year.

The action comes more than a year after the OFT responded to a super-complaint from consumer watchdog Which? and warned the airline industry to change practices or risk enforcement action.

OFT chief executive Clive Maxwell 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. Otherwise it is harder for them to shop around for the best deal.

“Because of our enforcement action, most airlines have already made their headline prices and other payment charges easier to understand by changing their systems and processes.

“The rest will complete changes in the coming months. We made it clear from the start that we would use all of our enforcement powers, including court action if necessary, but are pleased to have reached agreement with the airlines before court proceedings were required.”

The OFT said it believes people should not have to incur surcharges to use a debit card online. Debit cards are the online equivalent of cash which means that headline prices should be the price people can pay.

The OFT added that it believes that traders may still impose surcharges for credit cards, which can be more costly to process.

“However, it is critical that these charges are transparent and not sprung on shoppers towards the end of the booking process,” it said.