Tony Blair has acknowledged evidence about Saddam Hussein having actual weapons of mass destruction was wrong, during his keynote conference speech.
Blair says he has not neglected domestic issues
But the prime minister told Labour delegates in Brighton he could not apologise for having been involved in the effort to remove Saddam Hussein.
Mr Blair was interrupted briefly twice by anti-war and pro-hunting protests.
Much of his speech concentrated on his "mission" to create a Britain "for the many, and not the few".
Mr Blair, who arrived to chants of "four more years", was heckled first by a lone anti-war protester during his speech.
As the man was removed from the conference hall Mr Blair said: "That's fine sir you can make your protest - just thank goodness we live in a democracy."
A second larger protest by pro-hunt demonstrators took place some 15 minutes into Mr Blair's speech and several people were bundled from the room by stewards.
Later police arrested three people for disorderly conduct. All three were said to be party members.
Outside, thousands of pro-hunters protested against a hunting ban. Police have been working to prevent any repeat of clashes seen at a pro-hunting demonstration earlier this month in Parliament Square - a protest which also saw five men storm into the House of Commons chamber.
Voted for change
Mr Blair began his speech by expressing his "support and solidarity" for British hostage Ken Bigley and his family and sent his condolences to the families of the latest two British casualties in Iraq
Later, after outlining his ten priorities for a third term Labour government, Mr Blair said he wanted to tackle the issue of Iraq "head on".
BLAIR'S 1O PLEDGES FOR A THIRD TERM
Special help for first-time homebuyer
A new commitment to quality vocational skills
All parents to have the choice of a good specialist school but no return to selection at 11
Affordable and flexible childcare for the parents of all three- to 14-year-olds
Patient to choose hospitals and waiting time to 18 weeks
Security and dignity for everyone in retirement
Bringing broadband to every home and investment in the knowledge economy
Communities to have their own dedicated policing teams
ID cards and electronic registration to "all who cross our borders"
A fair deal for all at work
He said: "The problem is I can apologise for the information being wrong but I can never apologise, sincerely at least, for removing Saddam. The world is a better place with Saddam in prison."
He acknowledged that problems of trust stemmed from decisions taken since 11 September, 2001.
And he pledged he would make reviving the Middle East peace process a personal priority once US elections had happened in November.
Mr Blair also referred to a new war on global terrorism that is ongoing in Iraq.
But most of the speech, which received a standing ovation, was devoted to domestic issues, with the prime minister hailing what he said were Labour's achievements such as creating a stable economy, low unemployment and investment in public services.
The improvements had come about because the British had voted for change.
And he paid tribute to Gordon Brown as a "friend for 20 years" and the best chancellor Britain has ever had.
But Mr Blair went on to highlight inequalities that he said still existed in 21st Century Britain arguing that addressing these was "Labour's third term mission".
"If you have professional parents you are five times more likely to go to university, if you live in a smart part of town you are half as likely to be the victim of crime," he said.
"There is a glass ceiling on opportunity in this country. We have raised that ceiling - we haven't broken it."
Mr Blair also urged his party to be united adding that "with the courage of our convictions we can win the third term".
"It is worth the fight - now let's get out and do it."
The plea for unity comes amid a fresh outbreak in the apparent differences between Mr Brown and elections supremo Alan Milburn.
In a conference speech on Monday Mr Milburn, in what was widely seen as a direct attack on the chancellor, said the party needed to map out a radical new agenda rather than simply "shouting louder and louder" about its past record.
That came shortly after Mr Brown, elections supremo in 1997 and 2001, had addressed the conference spelling out Labour's achievements and his vision of building on those traditional Labour values in a third term.
The Lib Dems called on the prime minister to apologise to the families of the two soldiers killed in Iraq.
And party president Simon Hughes said: "Nobody in the free world wanted Saddam Hussein to continue there wasn't any disagreement about that - everybody wanted him out of the way.
"The problem was how to justify regime change in international law."
Tory co-chairman Liam Fox said the prime minister was "all talk" and was "out of touch".
The real reason voters no longer trusted him was because of broken promises over tax rises, tuition fees and over violent crime.
"Tony Blair is saying to us, 'trust me and having not delivered in the first two terms I will deliver in the third term', but the only thing the British people can be certain of in a third term is tax rises," he said.
"Mr Blair has let people down very badly and he has lost the trust of the British people.
"The bottom line is Labour has had seven years in office and they haven't delivered," he added.