London, Jan. 2 (Reuters): Europe’s biggest airline, British Airways, cancelled a London-Washington flight today as security fears grounded a US-bound plane for the seventh time in just over a week.

“It has been cancelled, that was based on advice from the UK government for a security reason,” a BA spokeswoman said.

Flight 223 was also grounded yesterday. On Wednesday the same flight was held on the tarmac at Washington’s Dulles International Airport. Passengers were questioned, but no one was arrested.

The US government raised its national security alert to the second highest level before the Christmas holidays, fearing hijackers could try to outdo the September 11 attacks on US cities that killed around 3,000 people.

It ordered international airlines to put armed marshals on certain flights, and dispatched fighter jets to escort some incoming Air France flights.

Washington has also provided intelligence on passengers that has prompted flight delays and cancellations.

The use of that intelligence was questioned after a newspaper report said Air France grounded three Paris to Los Angeles flights over Christmas because the FBI had confused the names of several passengers with suspected terrorists.

The FBI gave French police a list of six suspects and information indicating militants linked to al Qaida were planning to hijack an Air France jet, according to the Wall Street Journal Europe.

The report, citing French officials, said in one case a child’s name was confused with the head of a Tunisian-based terror group.

Two other “terrorists” on a list turned out to be a Welsh insurance agent and an elderly Chinese woman. The other three names were French citizens.

A French interior ministry spokeswoman declined to confirm or deny the report, saying only: “Some names were checked and they did not correspond to the people.”

A source close to French judges handling terror cases said the report could not be true, because US investigators had never given passenger names, only flight numbers.

Kevin Rosser, terrorism analyst at London-based Control Risks Group, said: “We are in a world now where governments feel they have to act on scraps of information. I think you have to understand the position governments are in politically. If, God forbid, something terrible happens and then it emerges they had information of a risk but did not do anything, they would be totally exposed politically.”

Asked why airlines did not simply remove suspect passengers and let the plane continue, he replied:“If you suspect one person is a threat, you don’t know if that person is working with other people on the flight.”

Two AeroMexico flights to Los Angeles from Mexico City were also cancelled this week because of suspicions would-be hijackers might have booked tickets.

Washington’s announcement it was ordering foreign airlines to place armed marshals on selected flights has drawn mixed reaction. While some nations announced their cooperation, several airline bodies criticised the order.

Britain said on Sunday it would put armed sky marshals on some planes. But British pilots say they are strongly against guns on planes.

“There is not enough being done about ground security,” a British Air Line Pilots Association spokesperson said today.

“No one is addressing this issue seriously. The emphasis seems to be on the plane once it is in the air and that is too late.”