The British Prime Minister, Mr Tony Blair, has recalled parliament for tomorrow and signalled his strong support for the United States as the world awaits its response to Tuesday's unprecedented terrorist assault.
The Prime Minister will make a statement to MPs before the Foreign Secretary, Mr Jack Straw, opens a full debate. The occasion will provide a first formal outing for the new leader of the Conservative Party, who will be announced this evening at the conclusion of a contest whose final stages have been totally eclipsed by the worldwide sense of emergency provoked by the attacks on Washington and New York.
As the Union flag flew at half-mast over 10 Downing Street, it was announced that Queen Elizabeth would break her holiday at Balmoral to attend a special service at St Paul's Cathedral in London tomorrow afternoon.
The queen has also ordered a special changing of the guard ceremony at Buckingham Palace this morning, at which a military band will play the American national anthem. In an unprecedented display at the palace this will be followed by a two-minute silence and sombre music in honour of the thousands believed killed or injured in Washington and New York.
Amid fears that many British subjects may have died in those atrocities, Mr Blair warned that Britain was involved in the unfolding tragedy "in a very real and direct sense".
While declining to speculate on what sort of help the UK might offer the US in identifying and punishing those held responsible for the attacks, Mr Blair told a Downing Street press conference: "Be under no doubt at all: we stand with the USA in this matter."
Following talks with the leaders of Russia, France and Italy - and shortly before a 20-minute telephone conversation with President Bush - Mr Blair said they were all agreed that "this was an attack not only on America but on the free and democratic world".
Beyond the American response, he said, the whole international community had now to consider where such terrorist groups were based, how they operated, were financed and supported, and how they could be stopped.
Welcoming the strong condemnation of the attacks by the British and American Muslim councils, the Prime Minister declared: "People of all faiths and all democratic political persuasions have a common cause: to identify this machinery of terror and dismantle it as swiftly as possible. With our American friends, and other allies around the world, this is the task to which we now turn."
The Prime Minister was speaking after the cabinet's emergency planning "Cobra" committee had agreed to maintain the "precautionary" security measures announced on Tuesday night for at least another 24 hours. The skies over central London remained a no-fly zone yesterday, with a series of rolling roadblocks the most visible sign of increased security around the City of London, where traders observed a minute's silence in memory of those who had lost their lives in Tuesday's attacks.
An estimated 50,000 transatlantic travellers suffered continuing delays to their plans as 140 scheduled flights out of Heathrow, and a further 50 out of Gatwick, were cancelled. The managing director of Heathrow, Mr Roger Cato, warned that normal services would not be resumed for at least a further 48 hours after American airspace had been re-opened.