A British inquiry into the Iraq war strongly criticised former Prime Minister Tony Blair and his government on Wednesday for joining the US-led invasion without a satisfactory legal basis or proper planning.

Blair responded that he had taken the decision to go to war in Iraq "in good faith", that he still believed it was better to remove Iraqi dictator Saddam Hussein, and that he did not see that action as the cause of terrorism today, in the Middle East or elsewhere.

The long-awaited inquiry report stopped short of saying military action was illegal, a stance that is certain to disappoint Blair's many critics.

"We have, however, concluded that the circumstances in which it was decided that there was a legal basis for military action were far from satisfactory," said John Chilcot, the inquiry's chairman, in a speech presenting his findings.

Blair argued the report should exonerate him from accusations of lying.

"The report should lay to rest allegations of bad faith, lies or deceit," he said in a statement.

"Whether people agree or disagree with my decision to take military action against Saddam Hussein; I took it in good faith and in what I believed to be the best interests of the country."

Prime Minister David Cameron said the government needed to learn the lessons from what went wrong in the build-up to Britain's joining the invasion of Iraq, in his initial response to a long awaited inquiry on the war.

Cameron, the outgoing Conservative prime minister, was answering questions in parliament on the Chilcot report.

"I think the most important thing we can do is to really learn the lessons for the future and the lessons he lays out quite clearly," he said, referring to the Chilcot report.

"The only point I would make is that there is actually no set of arrangements and plans that can provide perfection in any of these cases.

"Military intervention is always difficult, planning for the aftermath of intervention, that is always difficult and I don't think in this House we should be naive in any way that there's a perfect set of plans ... that can solve these problems in perpetuity."

Meanwhile, relatives of some of the British soldiers who died in Iraq said they would study the report to examine if there was a legal case to pursue against those responsible.

The Chilcot report said there was no imminent threat from Saddam in March 2003, and the chaos in Iraq and the region which followed should also have been foreseen. The invasion and subsequent instability in Iraq had, by 2009, resulted in the deaths of at least 150,000 Iraqis, mostly civilians, and displaced more than a million.

The report said Britain had joined the invasion without exhausting peaceful options, that it had underestimated the consequences of the invasion, and that the planning was wholly inadequate.

Published seven years after the inquiry was set up, the report runs to 2.6 million words - about three times the length of the Bible - and includes details of exchanges Blair had with then U.S. President George W. Bush over the invasion.

"It is now clear that policy on Iraq was made on the basis of flawed intelligence and assessments. They were not challenged and they should have been," Chilcot said.

He also said that Blair's government's judgments about the threat posed by Iraq's weapons of mass destruction were "presented with unjustified certainty".

Iraq remains in chaos to this day. Islamic State controls large areas of the country and 250 people died on Saturday in Baghdad's worst car bombing since the US-led coalition toppled dictator Saddam Hussein.

The inquiry rejected Blair's view that Iraq's post-invasion problems could not have been known in advance.

LEARNING LESSONS

The inquiry's purpose was for the British government to learn lessons from the invasion and occupation that followed, in which 179 British soldiers died.

Chilcot outlined a catalogue of failures made in the run-up to and aftermath of the war.

He said days before the invasion, Blair had been asked by the government's top lawyer to confirm Iraq had committed breaches of a United Nations Security Council resolution, which would justify war.

Blair said such breaches had been committed but Chilcot said: "The precise basis on which Mr Blair made that decision is not clear."

He also said Blair changed his case for war from focusing on Iraq's alleged "vast stocks" of illegal weapons to Saddam having the intent to obtain such weapons and being in breach of U.N. resolutions.

"That was not, however, the explanation for military action he had given before the conflict," Chilcot said.

British media have reported lawmakers led by the Scottish National Party were considering invoking an ancient law, last used in 1806, to impeach Blair in parliament.

"You cannot have a situation where this country blunders into an illegal war with the appalling consequences and at the end of the day there isn't a reckoning," SNP lawmaker Alex Salmond told Sky News.

The Sunday Times newspaper also reported that Labour leader Jeremy Corbyn - whose own position is in jeopardy after Britain voted last month to leave the European Union - was simply hanging on because he wanted to "crucify Blair".-Reuters