London: The chairman of a British public inquiry into the Iraq War that has yet to publish any findings after six years has defended his work against criticism by relatives of dead soldiers angry over how long it is taking.

The inquiry aims to shed light on every aspect of Britain’s involvement with Iraq from 2001 to 2009, from the build-up to the U.S.-led invasion in 2003 to the withdrawal of combat troops, and to identify lessons that can be learned.

The Iraq War, and in particular the role of former Labour Prime Minister Tony Blair in leading the nation into it, are still live political issues in Britain.

Publication is being held up by so-called “Maxwellisation”, a confidential process in which people who are to be criticised in the inquiry report are given advance copies of the draft so that they have a chance to defend themselves.

This has led to media speculation that some people were deliberately obstructing the process to protect their reputations and that the inquiry’s chairman John Chilcot was not being tough enough with those involved.

Chilcot said on Wednesday that the inquiry was on schedule and had met all its deadlines. Maxwellisation was essential for the report to be fair, accurate and robust, he said.

Despite mounting public pressure to publish, including from Conservative Prime Minister David Cameron, who said in June he was “fast losing patience” with the process, Chilcot has refused to announce a publication date.

“We expect to receive the last responses to our Maxwellisation letters shortly,” Chilcot said in a statement published on the inquiry’s website. That was the only hint of a timescale in his statement.

Jeremy Corbyn, the front-runner to become the new Labour Party leader, has said if he wins he will apologise for the war on the party’s behalf, and has also said Blair should be tried for war crimes if evidence shows he broke international law.

It emerged two weeks ago that lawyers representing 29 families of soldiers who were killed in Iraq were threatening to go to court unless Chilcot announced a date this year.

In public statements, lawyers and relatives accused Chilcot of failing to appreciate the strength of feeling among bereaved families seeking closure.

“My colleagues and I understand the anguish of the families of those who lost their lives in the conflict,” Chilcot said, confirming that he had received a letter from lawyers acting for families and had responded to their points.

Since the autumn of 2009 the inquiry has held more than 130 sessions of witness evidence, including two televised question sessions with Blair, and has received 150,000 documents.