Blair warns of new threat to Britain from al-Qa'ida

Tony Blair is to warn the British public that they will be directly involved in the battle against international terror.

In language not heard from a leading politician since the IRA bombing campaign, the Prime Minister will appeal to people to be on guard against the threat of al-Qa'ida attacks calculated to cause many civilian casualties.

Mr Blair also wants a public debate on how to cope with the disruption to civilian life which determined terrorists can cause – particularly if, like the 11 September attackers, they are as careless of their own lives as of others'. While calling for vigilance, he is also concerned that an over-reaction could "do the terrorists' work for them" by bringing parts of everyday life to a halt.

One factor adding to security fears is the prospect of war with Iraq. Although there is no proven link between Saddam Hussein's regime and al-Qa'ida, military action against an Arab state could inspire revenge attacks.

Yesterday, as more than 400,000 people took to the streets of Florence in the biggest demonstration yet against war on Iraq, pressure was mounting on Baghdad, including from its Arab neighbours, to take the first step towards abiding by the UN resolution passed unanimously on Friday. It gives Iraq until this Friday to accept the Security Council's demand for unfettered weapons inspections.

President George Bush yesterday repeated his warning to Iraq that it had no choice but to comply. "The resolution presents the Iraqi regime with a test, a final test," he said in his weekly radio address. "Iraq can be certain that the old game of cheat and retreat, tolerated at other times, will no longer be tolerated.

"Iraq must now, without delay or negotiations, give up its weapons of mass destruction, welcome full inspections and fundamentally change the approach it has taken for more than a decade."

Signals from Iraq were mixed. At a meeting of Arab League foreign ministers in Cairo, Iraq's Naji Sabri suggested that the UN text obstructed US war plans. "America's aggressive goal of using the Security Council as a cover for an aggression on Iraq was thwarted by the international community," he said.

However, Iraq's Babil newspaper, owned by President Saddam's son, said: "The American administration succeeded in making the UN its tool to influence policy."

In this atmosphere of public uncertainty over looming war and the al-Qa'ida threat, a Whitehall source said Mr Blair wanted "a mature debate about the sort of security measures that are appropriate when you are facing a new kind of terrorism, in that people are prepared to do things which in the past would have been considered beyond the pale".

The Prime Minister will deliver his warning during his annual speech tomorrow at the Lord Mayor's banquet. The speech will be his main foreign policy statement of the year, ranging over terrorism, the Iraq crisis, world poverty and the Doha agreement on world trade.

Insiders say that the current alarm is caused not by one "specific" intelligence report, but a series from around the world which all point to the possibility that al-Qa'ida may be about to strike again.

US intelligence sources now admit that the Afghanistan war made al-Qa'ida harder to stop, by compelling it to regroup as a mass of decentralised cells which tend to carry out their own attacks, rather than wait for instructions or prepared plans from the leadership.

In the past, US intelligence has got its most reliable information from captured al-Qa'ida documents and computer files, but these are much harder to find now that they are no longer in a central location, as they were in Afghanistan.