Ryanair, Michael O'Leary's Irish budget airline, lambasted the European Commission for double standards as it launched a landmark legal action to try to force it to investigate allegations of illegal state aid.

Ryanair, still stinging from its failed bid for Aer Lingus, its Irish rival, said that after "repeated failure" by the Commission to probe claims involving Air France, Lufthansa, Alitalia and Olympic Airways, it was resorting to the European Courts in a bid to kick-start the investigative process.

Ryanair claims that the French, German, Italian and Greek governments were involved in hundreds of millions of euros worth of illegal state aid through their support for financial bailouts for their flagship carriers. It says its battle to highlight the issue dates back at least five years; and has involved several requests for actions and a formal submission made more than a year ago.

"Since then, nothing's happened," a spokesman said. He said that Ryanair would not be seeking damages, but was demanding that the Commission "just follow through on the complaints".

The Commission blocked Ryanair's bid for Aer Lingus about a fortnight ago. The airline is preparing the paperwork for an appeal but to all intents and purposes its audacious bid has collapsed.

Jim Callaghan, Ryanair's head of regulatory affairs, accused the Commission of taking a "twin track approach" to state aid.

"On one hand they refuse to take action against serious violations of the state aid rules by national governments to protect their flag carrier airlines like Air France, Lufthansa, Alitalia and Olympic, while at the same time they launch bogus investigations against small regional and secondary airports like Charleroi," he said.

Several years ago the Commission investigated Ryanair's flights to Charleroi airport in France on competition grounds. It found against the Irish carrier, which has insisted it has been developing an underused route.

As it unveiled its preparations for a trip to the European courts, Ryanair listed a string of incidents where, it claimed, the Commission had failed to take action.

They include allegations that discounting of airport fees by the French Government has amounted to €1 billion (£675 million) of state aid over the past seven years and that the German Government allowed the state-owned Munich airport to rack up losses of more than €50 million a year on a new terminal that was built exclusively for Lufthansa, the German airline.

It said the Italian and Greek governments had "repeatedly given massive injections of state aid into their terminally ill flag carrier airlines".

The European Commission was not immediately able to respond.

"Ryanair is left with no alternative but to challenge the Commission's failure to investigate these unlawful state aid abuses in the European Courts," it said.

"It is time that the European Commission stops this twin track approach to enforcing the state aid rules. The same rules should be fairly applied to all airlines, and an end put to the unlawful state aid to the flag carriers".

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