Their comments follow the long-awaited release of the Chilcot report, which went into Britain's role in exhaustive detail and concluded that the senior US and British figures who drove the invasion had not exhausted diplomatic options, based their decisions on false intelligence and failed to develop a sound strategy for holding the country in the years afterwards. Former prime minister John Howard with former UK prime minister Tony Blair. Credit:Dave Thomson Mr Wilkie, who quit as a government intelligence analyst in 2003 because of concerns about the invasion, said it had been "the biggest security and foreign policy blunder in our country's history". He claimed neither the Lindt Cafe siege nor the 2005 Bali bombings would have happened if not for the 2003 Iraq invasion because it had "created the circumstances for the rise of the Islamic State". He accused then Mr Howard and former foreign minister Alexander Downer of taking the country "to war on a lie". He added there was a "pretty compelling case" that Mr Howard along with then US president George W. Bush and British prime minister Tony Blair had committed war crimes and should face an international court.

Mr Wilkie called for a full Australian inquiry and vowed to raise the issue with whoever became Australia's next prime minister when election counting has concluded. Andrew Wilkie gave evidence to a parliamentary inquiry in the UK in 2003. Credit:Julian Andrews "Until we have an effective inquiry into Iraq, people like John Howard and Alexander Downer won't be properly scrutinised or held to account," he said. "We won't learn the lessons to help prevent such a disaster again in the future … we won't fully understand the reforms that are needed in our parliamentary system to remove the unrestrained power from prime ministers to declare war." The Chilcot report – which runs to more than two million words – does not directly address Australia's involvement. Other commentators stopped short of calling for a comparable Australian inquiry. John Howard at a press conference on the Iraq war. Credit:Penny Bradfield

Peter Leahy, who was the chief of army from 2002 to 2008, said Australia needed a "discussion rather than an inquiry" but maintained that the Chilcot report highlighted how Australia needed to make better decisions about how to join its international partners, notably the US, on military missions. "Frankly, some of the decisions the United States, our senior partner in our strategic alliance, have made over the last 20 or 30 years have been a bit crook," Professor Leahy, who now heads the University of Canberra's National Security Institute, told ABC TV. Until we have an effective inquiry into Iraq, people like John Howard and Alexander Downer won't be properly scrutinised or held to account "I think it does give us this really important guide to the future, that we need to be able to take independent, sovereign decisions based on our own national interests and what the strategies might be." James Brown, a former army officer who served in Iraq and is now based at the US Studies Centre in Sydney, said Australia had made too little effort to learn from the mistakes after the 2003 invasion.

"This really points out by contrast [to Britain] that Australia's debate on Iraq is frozen in the politics of 2003 and is still focused on apportioning blame rather than better equipping us to make future decisions on military action," he said. Two key issues that emerged from Chilcot were the military strategy post-invasion and the fact that Britain had "spread itself too thinly between Iraq and Afghanistan". "We haven't begun to address those two questions in a substantive public way. Our debate stopped at the intelligence questions. We haven't even begun to look at the military effectiveness," he said. Foreign Minister Julie Bishop said any apology was "a matter for former prime minister John Howard" but stressed the decision to join the US was based on "the best information we had at the time". She said the Parliament and both sides of politics would "take responsibility" for the decision, saying it was "bipartisan up to a point", citing then Labor foreign affairs spokesman Kevin Rudd's expressions of support for the US.

Labor in fact expressly opposed the decision to go war at the time. Former Labor leader Kim Beazley, who took part in a major parliamentary inquiry into the Iraq war, said a comparable inquiry in Australia was not necessary. But he said that Labor's opposition to the war in 2003 on the basis that there was no evidence of a link between Saddam Hussein and al-Qaeda – which had carried out the September 11 attacks 18 months earlier – had been clearly vindicated. It had distracted from the effort in Afghanistan and taken Australia and its allies "down the garden path", Mr Beazley said. "It is quite obvious that that was not the fight that needed to be fought at that time," he said. "The consequences have been widespread and devastating."