The confrontation came as relatives of British soldiers killed in Iraq took the first step in a series of court actions over the war. They delivered a letter to Downing Street, demanding an independent public inquiry into the legality of the war and the sending of troops into a conflict on what they say were false pretenses. Blair was given a 14-day deadline to agree to an inquiry before the families make an application for a judicial review under the Human Rights Act.

“Each of our clients’ loved ones were killed when they had been told by you that they were fighting a war that was fully justified in international law in order to disarm a country that held weapons of mass destruction,” says the letter drawn up by the Birmingham-based Public Interest Lawyers.

The recent publication of the legal opinion on the war given by the attorney general on March 7, 2003, and leaks of official documents threw “into grave doubt the supposed justification and rationale for the war,” it says. At the very least, the letter adds, “a reasonable suspicion arises that you committed the U.K. … to war on the basis of regime change,” knowing that Lord Goldsmith advised this was an unlawful basis for war.

The letter was delivered to No 10. in the name of 10 families, including Reg Keys, whose son, Thomas, a military policeman, was killed in Iraq. Keys is standing against Blair in Sedgefield.

Earlier Tuesday, the widow of Coldstream Guardsman Anthony Wakefield, who was killed by a roadside bomb near Amara, southeastern Iraq, on Monday, said of Blair: “If he had never sent them over there, Anthony would still be alive.”

Rose Gentle, whose 19-year-old son, Gordon, was killed in Basra last June, said she was determined to take Blair to court for “war crimes.”

Phil Shiner, of Public Interest Lawyers, said the families hoped to achieve accountability. “They are entitled to know that their loved ones did not die in vain,” he said. He said the chance of the high court allowing a judicial review was “at least 50 percent.” The high court last year ruled that British soldiers in Iraq were restrained by the Human Rights Act in their treatment of Iraqis under their control. Some lawyers now say the government exposed British troops to unnecessary risk of death.

The families are also preparing a case for a private prosecution, charging Blair and the government with the crime of aggression — a move the attorney general warned Blair about in his March 7, 2003, advice.

Britain too has a particular responsibility. Last year the government renewed, with no debate, the U.S.-U.K. mutual defense agreement first negotiated in 1958 and regarded in Whitehall as a cornerstone of the countries’ special relationship. Bush said the agreement helped Britain maintain a “credible nuclear force,” giving weight to the argument put forth by the British American Security Information Council, an independent think tank, that it is an “open-ended arrangement for two named states to ‘disseminate’ information, technology and materials in their pursuit of more sophisticated nuclear weaponry.” Yet the purpose of the NPT, it points out, is “the prevention of the wider dissemination of nuclear weapons.” It also commits its signatories to work in good faith toward nuclear disarmament.

Yet what is happening? The U.S. is developing new nuclear warheads that don’t need testing and can be stored much longer than existing ones. The Bush administration is not discouraging U.S. nuclear scientists from asking Congress for money to develop a relatively low-yield bomb designed to attack underground bunkers — hiding places, in its view, for terrorists or the arsenals of “rogue states.”

Sophisticated equipment, including what is said to be the world’s most powerful laser, is being installed at the atomic weapons establishment at Aldermaston as part of a 2 billion-pound scheme that will enable Britain, with U.S. help, to produce a new generation of nuclear warheads, though the Ministry of Defense says there are no existing plans to do so. The technology will enable Britain to get around obligations imposed by the Comprehensive Test Ban Treaty.

The government turns on its head the logic of the NPT. Britain cannot disarm, it suggests, precisely because such weapons will inevitably spread. As the Ministry of Defense put it in its December 2003 defense white paper, the “continuing risk from the proliferation of nuclear weapons, and the certainty that a number of other countries will retain substantial nuclear arsenals, mean that our minimum nuclear deterrent capability, currently represented by Trident, is likely to remain a necessary element of our security.”

A decision on whether, or how, to replace Trident will have to be taken up in the next Parliament. Sir Alan West, the first sea lord, recently told the Commons defense committee: “There has got to be a decision made, an absolutely political decision: Do we want to keep nuclear weapons?”

Both the U.S. and Britain are muddying the waters in ways that will scarcely make nonnuclear states feel more secure. The U.S. has weakened the concept of “negative security assurances” — whereby nuclear states would not threaten or attack nonnuclear states with such weapons — by suggesting that it might use them in response to a biological or chemical attack, or even in other circumstances.

Britain’s defense secretary, Geoff Hoon, told M.P.’s earlier this month that the government “would be prepared to use nuclear weapons only in extreme circumstances of self-defense.” He continued: “A policy of no first use of nuclear weapons would be incompatible with our and NATO’s doctrine of deterrence, nor would it further nuclear disarmament objectives … Our overall strategy is to ensure uncertainty in the mind of any aggressor about the exact nature of our response, and thus to maintain effective deterrence.”

Does that really amount to effective deterrence? Whitehall officials sometimes give the impression that the main reason no British government would give up nuclear weapons is because it would leave France as the only European nuclear power. In other words, it is simply a matter of prestige and national pride.

The Bush administration has suggested that the “13 steps” agreed to at the last NPT review conference in 2000 simply constitute a “historical document.” The steps include a commitment to arms control, lowering the nuclear threshold and reaffirming “the ultimate objective of complete nuclear disarmament.”

While freeing the U.S. from any commitment, Bush wants other countries to make ever more binding ones. The NPT does not stop states from using enriched uranium to produce nuclear energy, as opposed to weapons. He does not want them to have any enriched uranium. Without irony, Bush stated last month: “We cannot allow rogue states … to undermine the NPT’s fundamental role in strengthening international security.” His target was, of course, Iran.

Iran, meanwhile, accuses the U.S. and others of hypocrisy by turning a blind eye to the nuclear arsenal of Israel, which, unlike Iran, has not signed the NPT.

The lesson nonnuclear states seem to be learning is that nuclear weapons earn you respect and deter foreign countries from attacking you. That is a very dangerous message, one that can’t be allowed to go unanswered.

The full picture of how the government manipulated the legal justification for war, and of the political pressure placed on its most senior law officer, is revealed in the Guardian Wednesday. It appears that Lord Goldsmith never wrote an unequivocal formal legal opinion that the invasion was lawful, as demanded by Lord Boyce, chief of defense staff at the time.

The Guardian can also disclose that in her letter of resignation in protest against the war, Elizabeth Wilmshurst, deputy legal advisor at the Foreign Office, described the planned invasion of Iraq as a “crime of aggression.” She said she could not agree to military action in circumstances she described as “so detrimental to the international order and the rule of law.”

Her uncompromising comments, and disclosures about Lord Goldsmith’s relations with ministers in the run-up to war, appear in a book by Philippe Sands, a Q.C. in Cherie Booth’s Matrix chambers and professor of international law at University College London. Exclusive extracts of his book “Lawless World” are published in Wednesday’s Guardian.

Lord Goldsmith warned Tony Blair in a document on March 7, 2003, that the use of force against Iraq could be illegal. It would be safer to have a second U.N. resolution explicitly sanctioning military action. “So concerned was the government about the possibility of such a case that it took steps to put together a legal team to prepare for possible international litigation,” writes Sands.

The government has refused to publish the March 7 document. It was circulated to only a very few senior ministers. All Lord Goldsmith gave the Cabinet was a later oral presentation of a parliamentary answer issued under his name on March 17. This appears contrary to the official ministerial code, which states that the complete text of opinions by the government’s law officers should be seen by the full Cabinet.

On March 13, 2003, Lord Goldsmith told Lord Falconer, then a Home Office minister, and Baroness Morgan, Blair’s director of political and government relations, that he believed an invasion would, after all, be legal without a new U.N. Security Council resolution, according to Sands.

On March 17, in response to a question from Baroness Ramsay, a Labor peer, Lord Goldsmith stated that it was “plain” Iraq continued to be in material breach of U.N. Resolution 1441. “Plain to whom?” asks Sands. It is clear, he says, that Lord Goldsmith’s answer was “neither a summary nor a précis of any of the earlier advices which the attorney general had provided.”

He adds: “The March 17 statement does not seem to have been accompanied by a formal and complete legal opinion or advice in the usual sense, whether written by the attorney general, or independently by a barrister retained by him.”

Separately, the Guardian has learned that Lord Goldsmith told the inquiry into the use of intelligence in the run-up to war that his meeting with Lord Falconer and Baroness Morgan was an informal one. He did not know whether it was officially recorded.

Lord Goldsmith also made clear he did not draw up the March 17 written parliamentary answer. They “set out my view,” he told the Butler inquiry, referring to Lord Falconer and Baroness Morgan. Yet the following day, March 18, that answer was described in the Commons order paper as the attorney general’s “opinion.” During the debate, influential Labor backbenchers and the Conservative front bench said it was an important factor behind their decision to vote for war.

Robin Cook, the former foreign secretary and leader of the Commons, Tuesday described the Guardian’s disclosure as alarming. “It dramatically reveals the extent to which the legal opinion on the war was the product of a political process,” he said. The case for seeing the attorney general’s original advice was now overwhelming, Cook added. “What was served up to Parliament as the view of the attorney general turned out to be the view of two of the closest aides of the prime minister,” he said.

Sir Menzies Campbell, the Liberal Democrat foreign affairs spokesman, said the government’s position had been seriously undermined. “The substance of the attorney general’s advice, and the process by which it was partially published, simply do not stand up to scrutiny,” he said. Sir Menzies added: “The issue is all the more serious, since the government motion passed by the House of Commons on March 18, 2003, endorsing military action against Iraq, was expressly based on that advice.” He continued: “The public interest, which the government claims justifies nonpublication of the whole of the advice, can only be served now by the fullest disclosure.”

Lord Goldsmith twice changed his view in the weeks up to the invasion. He wrote to Blair on March 14, 2003, saying it was “essential” that “strong evidence” existed that Iraq was still producing weapons of mass destruction. The next day, the prime minister replied, saying: “This is to confirm it is indeed the prime minister’s unequivocal view that Iraq is in further material breach of its obligations.”

The same day, Lord Boyce got the unequivocal advice he says he was after in a two-line note from the attorney general’s office. The extent of concern among military chiefs is reflected by Gen. Sir Mike Jackson, head of the army, quoted by Peter Hennessy, professor of contemporary history at Queen Mary College, London. “I spent a good deal of time recently in the Balkans making sure [Slobodan] Milosevic was put behind bars,” said Sir Mike. “I have no intention of ending up in the next cell to him in the Hague.”

Sands records that Lord Goldsmith visited Washington in February 2003, when he met John Bellinger, legal advisor to the White House National Security Council. An official later told Sands: “We had trouble with your attorney; we got him there eventually.”

A spokeswoman for Lord Goldsmith said Tuesday: “The attorney has said on many occasions he is not going to discuss process issues.” The March 17 parliamentary answer was the “attorney’s own answer,” she said, adding that he would not discuss the processes of how the document was drawn up.

The Department for Constitutional Affairs said it could not say if Lord Falconer had a role in drawing up the answer.

Schroeder’s speech was read by the German defense minister, Peter Struck, as the chancellor was ill with flu. Fischer said Sunday: “Schroeder wants the opposite of a weaker NATO. He wants to draft a grand design, a new strategic consensus across the Atlantic.”

Schroeder’s provocative proposal comes nine days before a NATO summit to be attended by George W. Bush, and follows what was billed as a conciliatory tour of Europe by new U.S. Secretary of State Condoleezza Rice.

U.S. Defense Secretary Donald Rumsfeld was in a conciliatory mood and ignored Schroeder’s suggestions. “NATO has a great deal of energy and vitality,” he said. Rumsfeld sought to end his feud with France and Germany by joking that his “old Europe” characterization “was old Rumsfeld.” “While there have been differences over Iraq, such issues among longtime friends are not new,” Rumsfeld said. “But we have always been able to resolve the toughest issues.”

But tensions between the U.S. and Europe over the conduct of the war on terror — in particular, how to stop Iran from building nuclear weapons — were obvious during the annual conference. Fischer urged America Sunday to embrace the E.U.’s diplomatic efforts to ensure Iran does not develop nuclear weapons. “If the United States were to engage positively, and I’m aware of how difficult that is, it would substantially strengthen the European drive,” he said. “If the whole process collapsed, then we would have to go to the [U.N.] Security Council.”

But Fischer suggested that sanctions could strengthen hard-line elements in the Iranian government and weaken democrats. “Iran is not Saddam Hussein,” he said. “We have there a contradictory mixture of very dark elements and democratic elements.” But his appeal appeared to fall on deaf ears. Members of the U.S. Congress attending the conference, notably Republican Sen. John McCain, who called Iran a “long-standing sponsor of international terrorism,” said they had little faith in the E.U.’s diplomacy.

Gholamali Khoshroo, Iran’s deputy foreign minister, said his country has no interest in an arms race. Unlike Israel, which has nuclear weapons, he said, Iran had signed the Non-Proliferation Treaty.

In Tehran, Foreign Ministry spokesman Hamid Reza Asefi reiterated warnings that the United States should not contemplate attacking Iran. “During the talks with the Europeans, we told them in clear terms to tell their American allies not to play with fire, and the Europeans clearly got our message,” the Associated Press reported Asefi as saying.

NATO Secretary General Jaap de Hoop Scheffer told the conference NATO could even help enforce a Middle East peace deal. De Hoop Scheffer has visited Jordan and is having talks with the Israeli government this month.

Tuesday the four Britons touched down on British soil at 5:02 p.m., after a battle by their families to secure their release. They had been picked up from Guantánamo Bay, land controlled by the United States on Cuba’s southeast tip, and flown directly to RAF Northolt, London.

Abbasi, 24, is the only one allegedly detained on the battlefield, in Afghanistan in December 2001. Richard Belmar, 25, and Moazzam Begg, 37, reportedly were arrested in Pakistan, while Martin Mubanga, 32, was detained in Zambia.

The fresh allegations of abuse of British detainees and their suffering came from Gitanjali Gutierrez, the U.S. lawyer for Abbasi. Gutierrez met with Abbasi, who comes from Croydon, south London, in Guant´namo last week, where he alleged that he was kept in isolation for 18 months in a windowless cell, he could not go outside to exercise, guards were removed to deny him any human contact (and monitored him by a remote camera), he was repeatedly injected with an unknown substance that triggered psychosis and he feared he would be beaten if he refused to comply with his captors.

Gutierrez, whose comments are subject to censorship by the U.S. military, told the Guardian her client was showing clear signs of the debilitating post-traumatic stress disorder and suffering panic attacks. She said: “The time in isolation led to mental breakdowns, he was talking to himself, hallucinating, sitting in the corner.

“We talked about the difficulties of reintegrating into regular life after the abuses and isolation he suffered. He had periods of psychosis that corresponded with the injections.” Three British detainees released last year also said they had been given mystery injections.

After touching down on British soil the four Britons were arrested under Section 41 of the Terrorism Act of 2000, suspected of involvement in the commission, preparation or instigation of acts of terrorism.

Sir John Stevens, the metropolitan police commissioner who made the decision to arrest, said: “The intelligence and the information was put to me over the weekend,” he said. “I have no other option but to arrest them. If their answers are satisfactory, then they will be released as soon as we can arrange it.” Police said they would be medically examined before interrogation. Because of the “unique circumstances” a family member would be allowed to see them, probably Wednesday. Muslim groups and the men’s families condemned the arrests.

Intelligence officials suggested Tuesday that there was no evidence any of the four presented a security threat. They expected all four to be released quickly, but insisted that the length of detention was up to the police. Muslim leaders who met with Britain’s top anti-terrorism officer, assistant commissioner David Veness, claimed he said the men would only be charged if they admitted criminal acts.

The four have been questioned at Guantánamo Bay up to nine times by MI5 officers. Any intelligence relevant to the war on terror would have been acted on already by Britain or the United States, anti-terrorism officials suggest. The four flew back to Britain on an RAF-C-17 military aircraft, accompanied by Scotland Yard anti-terrorist officers and two independent observers, one a Muslim. Police videoed the flight to guard against claims of ill treatment.

Up to 550 Muslim men remain in Guantánamo, including at least six British residents whom the government has declined to represent.