Ryanair has been fined €256m (£223m) by Italy’s competition authority for abusing its dominant market position to limit sales of tickets by online travel agents.

The authority said Europe’s largest airline had “implemented an abusive strategy to hinder travel agencies” via an “elaborate strategy” of technical obstacles for agents and passengers to make it difficult for online travel agents to sell Ryanair tickets and instead force sales through its own website.

The fine related to Ryanair’s conduct between April 2023 and at least until April 2025, the authority said on Tuesday. It said Ryanair had prevented online travel agents from selling tickets on its flights in combination with other airlines and services, weakening competition.

Ryanair said it would immediately appeal against the “legally flawed” ruling.

The Ryanair chief executive, Michael O’Leary, had decided to wage war on what he described as “pirate” travel agents, such as Booking.com, Kiwi and Kayak. O’Leary accused the travel agent industry of scamming and ripping off unsuspecting consumers by charging extra fees and markups on ticket prices.

O’Leary was prepared to accept lower ticket sales as he tried to prevent travel agents from selling tickets, forcing their passengers to fill out extra forms supposedly as a security measure. The abrupt removal of Ryanair flights from agents’ websites in late 2023 caused a drop in sales for the airline.

The lower sales dented Ryanair’s profits, although they have not prevented the Irish airline from rising to a record valuation of €31bn (£27bn). That has made it the world’s second most valuable airline, behind only the US’s Delta Air Lines.

O’Leary – who is known for his combative and often sweary criticisms of airports, rivals and regulators – is planning to hand over control of the business to a successor within the next five to 10 years. He will be given shares worth €111m (£97m) if he stays at the airline until the end of July 2028. He was already a billionaire on paper because of his shareholding.

Responding to the ruling, O’Leary said it was “an affront to consumer protection and competition law”.

He added: “The internet and the ryanair.com website have enabled Ryanair to distribute directly to consumers, and Ryanair has passed on these 20% cost savings in the form of the lowest air fares in Italy and Europe.

“Ryanair looks forward to successfully overturning this legally flawed ruling and its absurd €256m fine in the courts.”

The vast majority of Ryanair’s sales took place through its website even before the battle against online travel agents. However, the Italian authority said Ryanair had been guilty of “abuse of a dominant position” and using its “significant market power” in trying to stamp out the business.

Ryanair’s tactics included rolling out facial recognition procedures for people who bought tickets via a third party, claiming that was necessary for security. It then “totally or intermittently blocked booking attempts by travel agencies”, including by blocking payment methods and mass-deleting accounts.

The airline then “imposed partnership agreements” on agencies that banned sales of Ryanair flights in combinations with other carriers, and blocked bookings to force them to sign up. Only in April this year did it allow agencies’ websites to link up with its own services, allowing effective competition.

The competition authority said Ryanair’s actions had “blocked, hindered or made such purchases more difficult and/or economically or technically burdensome when combined with flights operated by other carriers and/or other tourism and insurance services”.