Passengers who bought their tickets since then have seen the tax rise included in the price, but those who booked further in advance either had to pay as they checked in or had the cost added to their credit card bills.

The tax, payable on all flights leaving British airports, is rising from five pounds (seven euros, 10 dollars) to 10 for domestic and short haul European flights and from 20 to 40 pounds for long haul travellers.

Business and first class passengers face increases of 10 pounds for short-haul flights and 40 pounds for long haul.

The increase has prompted tour operator First Choice to launch a legal challenge, while the Board of Airline Representatives, whose clients include BA, Air France, Virgin and Emirates, has warned it will consider court action.

Its chief executive, Mike Carrivick, told BBC radio that airlines could be liable for "well over 100 million pounds" under the increase. "These are amounts that cannot just be absorbed by all carriers," he said.

He also cast doubt on the government's environmental argument for the tax.

"There is no sign or indication as how the money raised from increase in (the tax) is being used for environmental reasons... There is no deterrent there, this is purely a money-grabbing exercise."

Some airlines including British Airways and Continental have absorbed the cost of the rise without passing it on to customers.

First Choice spokesman Dermot Blastland added that airlines were also annoyed the measure had been brought in so quickly.

Meanwhile, green pressure group Friends of the Earth called for stronger economic disincentives to put people off flying.

"The government must do more to make the cost of air travel reflect the damage that it causes to the environment," Dave Timms, their economics campaigner, said.

"The money raised should be used to support alternatives to flying such as rail travel and helping householders to cut the cost of going green." Official figures released Wednesday showed that carbon dioxide emissions from domestic flights went up 7.1 percent and from planes leaving Britain to go abroad rose 5.7 percent between 2004 and 2005.

Over the last decade, cheap flights to European destinations on budget carriers have become increasingly popular with Britons, despite concern over their environmental impact.

earlier related report
British aviation emissions continue to increase
London (AFP) Jan 31 - Aircraft carbon dioxide emissions in Britain continued to increase between 2004 and 2005, official figures showed Wednesday, prompting claims that the government is not doing enough on green issues.

Emissions from domestic flights went up 7.1 percent, while those from planes leaving Britain for international destinations rose 5.7 percent due to an increased number of flights.

Since 1990, aviation fuel emissions have more than doubled, said the Department for the Environment, Food and Rural Affairs.

Many Britons have developed a love affair with cheap domestic and European flights which have become widely available in the last 10 years, despite warnings about their environmental impact.

"These figures show that the government is still failing to tackle climate change," said Mike Childs, head of campaigns for green pressure group Friends of the Earth.

"The government must do more to ensure that the cost of flying reflects the environmental damage that aviation causes and it should abandon plans to allow new runways to be built."

Prime Minister Tony Blair is thought to view the environment as one of the so-called "legacy" issues on which he hopes to secure firm progress before leaving office later this year.

His government favours emissions trading schemes as a key plank in efforts to reduce greenhouse gas levels.

Environment Secretary David Miliband stressed that in terms of overall emissions, Britain was firmly on track to more than meet its targets under the Kyoto Protocol.

Related Links
Aerospace News at SpaceMart.com