PRESIDENT BUSH said yesterday that the plot to set off multiple explosions in US aircraft should serve as “a stark reminder that this nation is at war with Islamic fascists who will use any means to destroy those of us who love freedom”.

The President is always ready to tell his “fellow citizens” — as he did yesterday on a brief visit to Wisconsin — that “it is a mistake to believe there is no threat to the United States of America”.

Michael Chertoff, the US Homeland Security Secretary, wasted even less time in telling reporters at a breakfast-time press conference that the plan “was suggestive of al-Qaeda” — a view confirmed with greater certainty by officials speaking privately. However, with the fifth anniversary of the September 11 attacks looming and a new Oliver Stone film on the destruction of the World Trade Centre being released this week, the nerves of many American voters are already frayed and they do not require much prompting to worry about terrorism.

Although reports that Mr Bush was woken at his ranch in Texas yesterday morning by a call from Tony Blair were denied by the White House, the two leaders had been in regular touch — as recently as Sunday — about British police efforts to track and capture those behind the aircraft plot.

American authorities were told about a fortnight ago of an “accelerating plan” to target US airlines flying from Britain to Los Angeles, Washington and New York. One official was quoted yesterday as saying that British authorities would not have arrested the suspects “if they hadn’t thought these guys were ready to go — the trip line had been reached — they dropped the hammer when they did because they thought they were out of time”.

Mr Chertoff said that the plan was as “sophisticated as any we have seen in recent years”, adding: “This plot was well advanced. In other words, they had accumulated and assembled the capabilities that they needed, and they were in the final stages of planning.

“The terrorists planned to carry the components of the bombs, including liquid explosive ingredients and detonating devices disguised as beverages, electronic devices or other common objects,” he said.

It is not known if the alleged terrorists had gone so far as to book seats, but an FBI source told The Times last night that he believed that the terrorists had been examining routes but not specific flights.

Mr Chertoff drew comparisons with the Operation Bojinka plot in 1995 by Khalid Sheikh Mohammed, the mastermind behind 9/11, in which improvised bombs using liquid in contact lens solution containers would have been detonated on a dozen flights over the Pacific.

America has issued an unprecedented red alert on all flights to or from Britain, while raising to orange — the level below — the risk status of all other passenger aircraft.

Mr Chertoff said: “This is a precaution against any members of the plot who may still be at large. Given the amount of planning and effort that was put into this plot, I think it would be a little bit risky to assume that everything is shut down and the threat has gone.”

Federal air marshals are being sent to Britain to provide “expanded mission coverage” for flights to and from the US. Mr Chertoff emphasised that passengers should not cancel flights, saying: “We are screening out people who want to do harm to innocent travellers.”

Times Recommends

• Michael Jackson: Not the final chapter
• Indian Army spends10m rupees on golf buggies
• Brüno toned down for 15 rating