Aer Lingus has admitted that the total cost of its average European fare is higher than the €67 published in its 2005 annual report.

At a press briefing yesterday, Ryanair chief executive Michael O'Leary claimed the real fare was €93 when taxes and airport fees and charges were included.

Aer Lingus has refused to confirm the €93 figure, but yesterday acknowledged the €67 fare did not include these items.

The airline will have to include the higher fare in its Ipo prospectus and during its investment roadshows in the US, Britain and, possibly, Asia.

Mr O'Leary yesterday said Aer Lingus had been "understating" its fares for some time, but analysts were discovering that the average fare was much higher. The average Ryanair fare on European routes is €41.

According to the Aer Lingus annual report, the average European "flown fare" in 2005 was €67, while the average flown fare on its transatlantic routes was €241.

Asked about the short-haul fare yesterday, Aer Lingus said: "The figure in the annual report €66.81 does not include taxes, fees and charges. It is standard accounting practice to present the figure without taxes, fees and charges. We will going forward, as a publicly quoted company, quote inclusive of taxes and charges."

A spokeswoman said that, in its advertising, the quoted fare included taxes, fees and charges. The company said its average fare was not €93 as Mr O'Leary claimed.

The company said it was lower than this, but declined to offer a precise number.

Average fares are expected to come under serious pressure during the winter months. Mr O'Leary said average fares - often known as yield - could fall by between 5 and 10 per cent in the period between October 2006 and March 2007.