Liberal Democrat leader Charles Kennedy has issued a blistering attack on the prime minister over Iraq, as his party's conference gets under way.
Charles Kennedy is optimistic over his party's chances
Tony Blair did not present the "candid arguments" for the war "fairly and squarely" to the public and Parliament, he told BBC One's Breakfast with Frost.
Mr Blair had not "levelled with people" and this had unforgivably "eroded trust" in politics as a whole, he said.
Mr Kennedy also said he was optimistic of an electoral breakthrough.
The Lib Dems had proved their ability to beat both Labour and the Conservatives, he said.
But on Iraq, he said the prime minister still had not answered the question of whether he had told President Bush that Britain would be with the US in an Iraq war "come what may" before Parliament voted on the issue.
With "authoritative reports" indicating the Iraq survey group is set to report that there were no weapons of mass destruction in Iraq when the US-led war began, it was "increasingly likely" that regime change was the real motive for the war, Mr Kennedy said.
He also urged the government not to take any "irrevocable decisions" on the future of Iraq or send more UK troops there while Parliament was in recess for the party conferences.
Turning to the party's draft manifesto, launched ahead of this week's conference in Bournemouth, Mr Kennedy said the "domestic agenda was paramount".
The Lib Dems have pledged to, among other things, scrap tuition fees, introduce free personal care for the elderly and replace the council tax with a system of local taxation.
These policies would be paid for by introducing a 50% tax rate on those earning over £100,000 a year.
Mr Kennedy said seven out of 10 people would be better off with the Lib Dems' planned system of local taxation replacing the council tax.
"The majority within that proportion of winners will be pensioners and single householders. However, what we also say, is that you've got to look at this within the broader range of other policies we are introducing for other people.
"Younger people will benefit from the fact that if their children are going to become university students... they won't be saddled with the colossal amounts of debt that they are going to incur.
"Their elderly parents ... they will enjoy a sustained level of income and security into their older age and not have to sell or realise the family home because they don't receive free long term personal care," he added.
Mr Kennedy also defended the fact that there was only a small mention of Europe in its pre-manifesto document, suggesting that voters knew what Lib Dem policies were on this issue following the European elections in June.
But there is a debate amongst Lib Dem MPs about whether they should adopt more right-wing policies.
Some think such a change in direction would attract more Conservative votes in the party's most winnable seats.
Mr Kennedy believes recent by-election and council successes show the party can compete in both Labour and Tory heartlands.
He will also be keen to impose himself on this conference after illness at the party's spring conference generated speculation over his leadership.
He said: "We do best... when we present ourselves as what we are - an independent, growing campaigning force addressing the relevant needs of people with a view to Britain's future.
"The more we do that people will make their own minds up about where we land beyond the next election.
"But every indication from this Parliament is that we will emerge from that election a bigger, better stronger and more pivotal to the future of British politics."