He suggested the decision by President Barack Obama to withdraw from Iraq was to blame.

"There is a view, which I think has a lot of merit, that if the process or the aftermath of the surge had been reinforced by a greater continuing Western, particularly American, presence, the situation would have been lot more stable," Mr Howard said.

The Chilcot inquiry was damning of Britain's decision to back the US-led invasion, saying it was based on unchallenged and flawed intelligence, was launched before diplomatic options were exhausted, and that the risks were never considered.

It found then Iraqi dictator Hussein posed "no imminent threat".

Protesters wearing a Tony Blair mask, left, and George W. Bush mask pose before the publication of the Chilcot report in London. AP

The report led Tasmanian independent MP Andrew Wilkie – who resigned from his job as an intelligence official at the Office of National Assessments in protest over the 2003 decision – to renew his call for a proper inquiry into Australia's involvement, and to accuse Mr Howard of war crimes.

"We know this now more clearly than ever that the Howard government took us to war on a lie. Every time it's said that Iraq had a massive arsenal of weapons of mass destruction and it was co-operating with al-Qaeda, it knew that was not the case, that it was either clearly not the case or, at best, for them it was ambiguous," he said.

"They took us to war on a lie. No wonder John Howard and Tony Blair and George W. Bush do stand accused of war crimes. I'd like them to see an international court."


Today it is frequently argued that destabilisation of the region caused by the invasion – with no plan for how to deal with the aftermath – gave rise to the spread in popularity of al-Qaeda and the establishment of Islamic State. It also hampered the effort in Afghanistan.

Former British prime minister Tony Blair has come under fire in the Chilcot report. Getty Images

In the US, Republican presidential candidate Donald Trump uses the ongoing chaos caused by the war as an argument against his Democrat rival Hilary Clinton, who, as a New York senator, voted for the war in 2003.

Mr Howard said there was no need for another inquiry, and he believed at the time the intelligence was genuine.

"In the years that have gone by, there's been this constant claim that we went to war based on a lie. There was no lie. There were errors in intelligence, but there was no lie," he said.