The increase in passenger charges from £5 per journey to £10 was announced in the annual pre-budget speech by British chancellor Gordon Brown. Brown has been under pressure from environmentalists to introduce measures to curb air travel.

Ryanair's response was typically dismissive.

"It is an outrage that Gordon Brown proposes to tax the poor. This tax won't make the slightest difference to the rich fat cats in business class and it won't do anything for the environment, " said a spokesman for the company.

Ryanair chief executive Michael O'Leary has been a vocal critic of the environmental lobby in the UK, which has been exhorting both governments and airlines to control carbon emissions and reduce unnecessary air travel. O'Leary refers to environmental campaigners as "econuts, idiots and headbangers".

British Airways chairman Martin Broughton, however, is adopting a more conciliatory tone. In a speech last week at the aviation club in Britain he said it was vital that the industry be seen to be environmentally responsible, and criticised O'Leary for his frequent tirades against lobbyists.

"We can't pollute the atmosphere further with a volley of Ryanair verbals and pretend to ourselves that the problem doesn't exist. That's just dumb, " he said.