Just 30% think the prime minister has got the relationship about right, against 63% saying he has tied Britain too closely to the US.

Carried in the wake of the accidental broadcast of the prime minister's conversation with President Bush at the G8 summit, the poll finds opposition to this central element of the prime minister's foreign policy among supporters of all the main parties.

Even a majority of Labour supporters - traditionally more supportive of Mr Blair's foreign policy position - think he has misjudged the relationship, with 54% saying Britain is too close to the US. Conservatives - 68% - and Liberal Democrats - 83% - are even more critical.

And voters are strongly critical of the scale of Israel's military operations in Lebanon, with 61% believing the country has overreacted to the threats it faces.

As pressure grows for a change of strategy, the poll finds that only 22% of voters believe Israel has reacted proportionately to the kidnapping of soldiers and other attacks from militant groups in southern Lebanon. Israel has repeatedly sought to assure the world that its actions are a legitimate response to threats to its own territory, including missile attacks on the north of the country.

The finding follows more than a week in which Mr Blair has come under fire for echoing US caution about the practicality of an immediate ceasefire in the Middle East and for allying himself too closely to Israel.

At a press conference in London yesterday Mr Blair defended his position and expressed sympathy for the plight of the Lebanese. "What is occurring in Lebanon at the present time is a catastrophe. Anybody with any sense of humanity wants what is happening to stop and stop now," Mr Blair said. He added: "But if it is to stop, it must stop on both sides."

This did not amount to switch in policy but a change in emphasis, in part to answer critics who accuse him of being indifferent to the plight of the Lebanese. A British official said: "He wants to make it clear he has the same feelings as everyone else but the job of government is to find an answer. The proof of the pudding is if we are able to find a way through."

Unlike other international leaders, Mr has refused to describe the Israeli attacks on Lebanon as disproportionate. But the official said there was a difference between what Mr Blair said in public and what Mr Blair and other members of the government said to the Israelis in private.

Public unease about Israel's approach is reflected in public attitudes to the Iraq war, with support for the overthrow of Saddam Hussein falling to a record low since military action began in March 2003.

Although a solid core of Labour supporters - 48% - still think the war was justified, overall only 36% of voters agree - a seven-point drop since the Guardian last asked the question in October 2004.

Older voters, Conservatives and Liberal Democrats and people living in the south are particularly critical, suggesting the anti-war movement has a base of support well beyond student groups and the left.

Support for the war reached 63% in April 2003, in the wake of early military success. Now a narrow majority of voters - 51% - believe it was unjustified, the highest proportion for more than two years.

Amid fears that the armed forces are operating at the limit of their resources, voters also believe that British troops are doing more harm than good in Iraq and Afghanistan.

They are more concerned by the role of British forces in Iraq than Afghanistan, with 36% saying their presence is making the situation worse in Iraq against 29% who think this is true of Britain's more recent deployment in southern Afghanistan.

But both findings outweigh the proportion of voters who think British troops are improving the situation on the ground: just 19% of all those questioned think they are making progress in Iraq and 23% think this is the case in Afghanistan. Around a third of voters think that at best British forces are making no difference one way or the other in the two countries.

There is also minimal public appetite for fresh foreign policy commitments, such as a multinational force in Lebanon. An overwhelming proportion of voters think current deployments are already overstretching Britain's military resources: 69% agree; 19% do not.

Conservatives - 78% of whom believe the armed forces are overstretched - are especially concerned, despite David Cameron's support for an interventionist policy, symbolised by his visit to troops in Kandahar yesterday.

- ICM Research interviewed a random sample of 1,001 adults over 18 by telephone on July 21-23. Interviews were conducted across the country and the results have been weighted to the profile of all adults. ICM is a member of the British Polling Council and abides by its rules.

Ms Williams was awarded the Nobel Peace Prize 30 years ago, when she circulated a petition to end violence in Northern Ireland after witnessing British soldiers shoot dead an IRA member who was driving a car. He veered on to the footpath, killing two children from one family instantly and fatally injuring a third.

Ms Williams's petition had tens of thousands of Protestant and Catholic women walking the streets together in protest. Now the former office receptionist heads the World Centres of Compassion for Children International, a non-profit group working to create a political voice for children.

"My job is to tell you their stories," Ms Williams said of a recent trip to Iraq.

"We went to a hospital where there were 200 children; they were beautiful, all of them, but they had cancers that the doctors couldn't even recognise. From the first Gulf War, the mothers' wombs were infected."

"As I was leaving the hospital, I said to the doctor, 'How many of these babies do you think are going to live?'

"He looked me straight in the eye and said, 'None, not one'. They needed five different kinds of medication to treat the cancers that the children had, and the embargoes laid on by the United States and the United Nations only allowed them three."

Wrapping up the three-day forum yesterday, delegates agreed to a 26-point action plan.

"There can be no sustainable peace while the majority of the world's population lives in poverty," they said.

"There can be no sustainable peace if we fail to rise to the global challenge presented by climate change."

"There can be no sustainable peace while military spending takes precedence over human development."

"The president is indicating that he will not either enforce part or the entirety of congressional bills," said ABA President Michael Greco, a Massachusetts attorney. "We will be close to a constitutional crisis if this issue, the president's use of signing statements, is left unchecked."

The report seemed likely to fuel the controversy over signing statements, which Bush has used to challenge laws ranging from a congressional ban on torture and a request for data on the Patriot Act, to whistle-blower protections and the banning of U.S. troops in fighting rebels in Colombia.

Administration officials describe them as a part of routine presidential practice.

"Presidents have issued signing statements since the early days of our country," White House spokeswoman Dana Perino said Sunday. "... He is exercising a legitimate power in a legitimate way."

Bush vetoed his first bill last week, a measure approved by Congress relaxing his limits on federal funding for human embryonic stem cell research. But he has on many occasions signed bills, then issued statements reserving the right not to enforce or execute parts of the new laws, on the grounds that they infringe on presidential authority or violate other constitutional provisions.

Determining the rarity of this approach is a matter of some dispute. The Justice Department has said Bush has issued 110 signing statements, compared with President Bill Clinton's 80.

The ABA task force, chaired by prominent Miami attorney Neil Sonnett, cites research that Bush in his signing statements has collectively lodged more than 800 challenges to provisions of laws passed by Congress.

The report will be considered by the full ABA at its meeting next month.

IT looks like an ordinary freight train. Drab, workmanlike and uninteresting.

But it carries a lethal nuclear cargo that could cause untold deaths if targeted by terrorists. Once a week the diesel-powered locomotive goes unnoticed as it pulls four trailers hundreds of miles around our rail network.

Few are aware the train trundling from the Kent countryside to Cumbria carries radioactive flasks of spent uranium fuel rods.

After the July 7 terror bombings most would think such a vulnerable target would be under the tightest of security.

But a Daily Mirror investigation has revealed a series of astonishing flaws that will inspire horror and disbelief. Incredibly, I was able to place a device that could have been a bomb on the 12-ton cargo as the train sat in sidings at a North West London rail depot.

I approached in daylight after the wagons were left seemingly unattended for almost 10 minutes. The driver, who was taking a break nearby, even left the engine running while myself and a Mirror photographer stood beside the radioactive material.

For two months we had monitored the trains that carry waste from nuclear power stations to the Sellafield reprocessing plant.

We discovered the flasks are frequently open to a potential terror strike while the locomotives wait in a depot.

The vast North West London yard is just a short walk from a sports stadium, a large hospital and one of the capital's major roads. It is surrounded by housing estates. All in all, the perfect weak spot for a terror strike.

Nuclear transport expert Dr John Large has estimated an attack on containers of radioactive waste could kill 8,000 people in an instant.

Thousands more would become victims as a vast poisonous cloud of up to a hundred square miles drifted across Britain.

On Wednesday, the nuclear train pulled in to the depot on time at 7.54pm after leaving

Kent's Dungeness Power Station three hours earlier and travelling slowly through stations at Ashford, Sevenoaks, Tonbridge and South London. On arrival the crew of one man and one woman climbed from the cab and walked to a hut 100 yards away.

Two private security guards initially patrolled the train while it stood waiting for a replacement crew for the next leg of the journey north. But they were only visible for 15 minutes before disappearing.

Suddenly there was no one to see us. As we approached the train the four flasks, each containing enriched fuel pins, were clearly indicated by their radioactive warning signs.

We were able to take photographs for several minutes. Anyone with a basic knowledge of driving trains could have hijacked it. By the time we walked past the front of the train the replacement driver was in position, but he did not challenge us. Minutes later he pulled out, heading through Milton Keynes, Rugby, Crewe and Warrington, before arriving at Sellafield.

My only identification as a legitimate rail worker was a fluorescent orange jacket and hard hat, on sale at any builders' merchants.

And this was not a one-off. It was the tenth time I had wandered freely into the depot.

Not once was the main entrance gate shut. The security booth, containing a bank of blank screens for CCTV cameras that never appeared to be functioning, was always empty. Drivers and track maintenance workers who saw us walking between the rails nodded or said hello. I was never asked for a security pass, supposedly obligatory in a fenced-off area. Other trains arrive from Suffolk's Sizewell A power station. Some get there in the middle of the night and wait for long periods in the virtually unlit yard.

A rail insider said: "Security is a joke. All you need to do is find the gate and you can wander at will. If you wear an orange jacket no one will ever ask what you are doing."

Last night nuclear experts and politicians said they were horrified by the Mirror's findings. Dr Large said: "I'm appalled. Every one of these trains would be a potential target for terrorists. If you had an incident in London, I estimate that 190,000 people would have to be evacuated. Those flasks were designed to counter accidents. But they weren't designed to counter the likes of al-Qaeda."

Lib Dem environment spokesman Chris Huhne said: "This is a shocking revelation."

A spokeswoman for Direct Rail Services initially claimed it would not have been possible to get close to the nuclear flasks while the train is stationary at Brent yard.

But after seeing our evidence she said: "The entire journey is protected by very stringent security. However, having seen these pictures we will speak with our security people. A full investigation will be carried out."