British airline pilots have urged the government to examine the quality of intelligence that led to the cancellation of trans-Atlantic flights.
British Airways cancelled four flights on Sunday and Monday
The US intelligence prompted British Airways, Air France and Continental Airways to ground flights.
The authorities said there was a specific threat to international air travel from al-Qaeda.
However, the pilots' union said the quality of the intelligence should be examined by the British government.
The general secretary of the British Airline Pilots' Association,
Jim McAuslan, said: "We have to take all these intelligence briefings very seriously
but we are asking the British government to examine the strength and validity of
Continental Airlines flight 17 Glasgow-LA 1 Feb
BA flight 203 London-Miami 1 Feb
BA flight 223 London-Washington 1 Feb & 2 Feb
BA flight 222 Washington-London 1 Feb & 2 Feb
Air France AF026 Paris-Washington 1 Feb & 2 Feb
Air France AF027 Washington-Paris 1 Feb & 2 Feb
"These cancellations were made because of US intelligence and the airline is
quite right to cancel the flights.
"But we are pressing the government to examine these claims from the USA,
particularly as President (George) Bush has called for an examination of the
quality of intelligence before and during the Iraq war."
His concerns were echoed by terrorism specialist Simon Reeve, author of the book on al-Qaeda, The New
"I think some of the evidence, some of the intelligence
surrounding these threats is tenuous to say the least," he said.
"But nobody in the intelligence community or airport security will want to
take the chance of sending a plane into the air if there is even a whisper of a
While a spokesman for the Department for Transport refused to discuss the nature of
the intelligence from the US, he did say: "Our intelligence services are in touch with their American counterparts and keep security under regular and constant review and take
whatever response is necessary."
British Airways and Air France both cut four flights on Sunday and Monday, followed by Continental Airways on Sunday.
They did so after the US Department of Homeland Security said there "was specific credible threat information that was shared with some foreign governments, including the British and French Governments, and the decisions were made to cancel these flights."
US officials believe al-Qaeda is again trying to target international flights.
But neither the airlines nor the UK government has commented on this.
American media quoted sources as saying the threat was new information from an informant, which was corroborated by other sources who named specific flights.
BA 223 was the subject of concern early in
January, when it was cancelled twice because of security
fears and then delayed for hours several more times.
Defence analyst Paul Beaver said: "People in Washington are saying that this is basically good, straightforward intelligence about flight numbers and destinations.
"Between the first of February and somewhere around the 21st or 23rd of February, there seems to be a period where there is a heightened risk."
Mr Beaver said al-Qaeda was changing tactics, posing a continuing problem for authorities.
"Al-Qaeda adapts and evolves. What they are after now is American, British and European passport-holders.
"They are after clean-looking people, business people or holiday travellers who appear to be smartly dressed.
"In other words, they are trying to put off the intelligence services."