Ryanair has responded to a request from the Walloon Regional Government for the return of illegal airport subsidies by asking that it write to it in English rather than French.

The region, and Charleroi Airport, are seeking the return of €4 million following a decision by European Union regulators in February that incentives which Ryanair received for setting up a hub at the airport were illegal.

Ryanair is appealing the ruling.

In May, Ryanair chief executive Mr Michael O'Leary said that a request for the return of money by the Walloon Regional Government had been met with a curt response.

The authorities at Wallonia were recently given until September 15th to begin recovering the funds.

A letter was sent out on Monday of last week and Ryanair responded to reports that this had occurred by saying it would dismiss any such request.

Yesterday Ryanair said that it had received an 18-page letter from the Walloon Regional Government late on Friday evening.

"Ryanair became aware of this letter on Monday morning and immediately wrote to the Walloon Regional Government requesting an official translation of this letter in English in order to ensure that there are no ambiguities or misunderstandings in the text."

"As soon as Ryanair receives this letter in English, we will respond immediately and will publish full details of this response."

The controversy arises out of the deal Ryanair negotiated with the Belgian airport when contracting to use Charleroi as a hub for a 15-year period.