TONY BLAIR’S integrity was forced back to the centre of the election campaign last night with the leaking of confidential advice from the Attorney-General voicing doubts about the legality of the Iraq war.

The disclosure by Channel 4 of Lord Goldsmith’s advice to Mr Blair electrified the campaign on a day when the Prime Minister also moved towards ruling out British membership of the euro in the next Parliament.

The twin events produced by far the most dramatic day of the 2005 election. Lord Goldsmith’s document told Mr Blair only ten days before the invasion in March 2003 that he could not be confident that a court would regard military action as lawful.

He was later to conclude categorically that the invasion of Iraq was legal and last night in an emergency statement Lord Goldsmith insisted that the leak “stood up” the case that the Government had been making. Far from showing that he believed war would be illegal, the advice showed that he had gone through all the complicated legal issues surrounding military action before concluding that it would be lawful.

The new disclosures came as the latest Populus poll for The Times showed that only a quarter of voters now trusted Mr Blair. Even so, Labour has a comfortable nine-point lead in the latest tracker poll.

The disparity between Lord Goldsmith’s private advice to the Prime Minister and the categorical statement less than two weeks later that the war was legal was seized upon by the opposition parties and seemed certain to dominate campaigning for the next few days. But Mr Blair will insist that the disclosures prove that the legal doubts were explored before the invasion took place.

The disclosure of the advice came at almost the same time as Mr Blair, in an unexpected move, admitted that euro entry “doesn’t look very likely”. Previously the Government had maintained that it favoured membership in principle and was keeping the option open. His remarks appear to pre-empt the decision for the next few years. “If the economics aren’t right, if it won’t help your country economically, you don’t do it,” Mr Blair said.

“Now, at the moment there is no part of business and industry clamouring to say we need this for our economy, so it doesn’t look very likely.”

Labour remains in a strong position in the Populus poll on 40 per cent, ahead of the Tories on 31 per cent and the Liberal Democrats on 21 per cent, all unchanged since yesterday.

However, nearly a half of the public say that they once trusted Mr Blair but have lost trust in him. This includes nearly three in ten Labour supporters. Just over a fifth of all voters (22 per cent) say that his handling of Iraq led to their loss of trust. But an even higher proportion (26 per cent) blame his failure to live up “to his promises in general”.

This leaves just a quarter of voters (24 per cent) saying that they trust the Prime Minister. This includes nearly two thirds of Labour supporters, but only 7 per cent of either Tories or Lib Dems. The poll is based on interviews on Monday and Tuesday after Iraq became central to the campaign and Michael Howard and Charles Kennedy attacked his trustworthiness.

An earlier Populus poll showed a continuing high level of opposition to joining the euro. Some 59 per cent would oppose joining, with just 35 per cent being in favour. Only among Labour supporters is their a narrow majority, 50 to 46 per cent, in favour.

Moreover, only a third of voters think Mr Blair has learnt his lessons from the Iraq war, from the criticisms of his informal style of government, and from people saying that he has not done enough to improve public services. Only just over a quarter say he has learnt the lessons of the criticisms that his Government is too concerned with spin. In last night’s interview on Sky News Mr Blair made plain that if elected he would not be launching another push for entry.

“At the moment it doesn’t look very likely, does it, because the economics aren’t in the right place,” he said.

His comments came after a speech this week by Gordon Brown — who has always been cooler on the euro and is expected to succeed Mr Blair — which emphasised that the five tests would be applied rigidly through the next Parliament and if necessary beyond.

Mr Blair spent most of yesterday trying to avoid rising to Mr Howard’s charges of lying which have been attacked by religious leaders from the Jewish and Christian traditions. The Bishop of Birmingham, Dr John Sentamu, said the tactic was reminiscent of the 1997 campaign when the future Prime Minister was depicted as having devil’s eyes. “That kind of personal attack is not acceptable in a civilised country.”

A member of the Chief Rabbi’s cabinet, Rabbi Yitzhak Schochet, Rabbi of Mill Hill Synagogue, said: “I am all that little bit more disturbed considering that Michael Howard is Jewish and it goes against the grain of fundamental Jewish principles to start disparaging people and personalising the agenda.”

The Chancellor rejected allegations that Mr Blair had lied over Iraq. In a BBC interview Mr Brown made a point of saying that he and Mr Blair were working together as part of the same team. Asked whether he trusted Mr Blair, he responded: “Yes, I do.”

Mr Blair said in his Sky News interview: “I have never told a lie . . . I did not lie over Iraq.”

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