The official report of US weapons inspectors in Iraq shows sanctions against the Saddam regime were not working, the Prime Minister has said.
Tony Blair made his comments during a trip to Africa
The Iraq Survey Group report published on Wednesday said Saddam was "doing his best" to get round the sanctions, according to Tony Blair.
He said Saddam "never had any intention of complying with UN resolutions."
Mr Blair said the report made clear that there was "every intention" on Saddam's part to develop WMD.
Mr Blair made the comments during a trip to Africa on Wednesday, ahead of the official publication.
BBC chief political correspondent Mark Mardell called them "remarkably defiant".
But he added: "Yet again Tony Blair is having to talk to the British people, explain what he did, about the war.
"Last week he had to admit he had a real problem with trust - and there is no real way... of solving that."
Much of the content of the report has been anticipated since a draft of the report was leaked last month.
Foreign Office Minister Baroness Simons told BBC News the report said Saddam had been "very close" to breaking sanctions.
"It was his overriding aim - that was what he was about."
The report made clear Saddam had maintained the "intellectual capabilities" and laboratories to develop WMD, Baroness Simons added.
But former UN chief weapons inspector Hans Blix told BBC News sanctions had "contained" Saddam.
"They did destroy all the biological and chemical weapons and the nuclear weapons sector was also all cleared up.
"Had we had a few months more we would have been able to tell the CIA and others that there were no weapons of mass destruction."
But US President George Bush had been "desperate" to be able to say there were WMD, Dr Blix added.
Earlier, Foreign Secretary Jack Straw said the report showed Saddam posed a bigger threat than previously imagined.
Jack Straw says Saddam's intentions were a huge threat
It was now no surprise the Iraq Survey Group had found no WMD, he said.
But Mr Straw, speaking in Baghdad, said "the threat from Saddam Hussein in terms of his intentions" was "even starker than we have seen before".
Anti-war MP Robin Cook said the report showed the containment policy had been working and war had been unnecessary.
Earlier, Mr Straw told reporters: "I personally am in no doubt whatever... that had we walked away from Iraq and left Iraq to Saddam, Saddam would have indeed built up his capabilities, built up his strength and posed an even greater threat to the people of Iraq and the people of this region than before."
His comments were backed by Iraq's Deputy Prime Minister Dr Barhem Saleh.
He said anyone who doubted that Saddam Hussein had possessed weapons of mass destruction only needed to visit Halabja - where the former Iraq dictator had gassed thousands of Kurds.
Dr Saleh said it would be "very surprising" if press leaks that the survey group had found no WMDs turned out to be true.
"We know Saddam had weapons of mass destruction. We know he used weapons of mass destruction," Dr Saleh said, adding that in his view Saddam Hussein was himself a weapon of mass destruction.
What the press leaks had left out was how Saddam Hussein had been diverting money from the Oil-for- Food programme to buy new weapons, Dr Saleh added.
But former foreign secretary Robin Cook, who quit the Cabinet over the decision to go to war, said the international community had always known Saddam Hussein had ambitions to have such weapons.
That was why there had been a policy of containment which had been very successful because he had not had a single weapon of mass destruction, he told the BBC.
"We now know that we did have the extra time that Hans Blix wanted to finish the job. The war was unnecessary."
The Conservatives said the report provided further evidence that Mr Blair had not told
the truth about the war.
Shadow foreign secretary Michael Ancram said Mr Blair should have "trusted the British people with the truth."
"Instead he misled the British people and in doing so he has lost the people's trust."
The Liberal Democrats said the report justified the policy of deterrence and containment.
Foreign affairs spokesman Menzies Campbell said: "It most certainly does not provide any support for the government's view that the threat from Saddam Hussein was so acute that only immediate military action would do."