Sir John Chilcot says he understands the "anguish" felt by families of British soldiers killed in Iraq as he attempted to explain why his inquiry has yet to report its findings after six years.
In a statement, Sir John claimed the delays are due to the Maxwellisation process, which gives those criticised in the report a right to respond, but the process will be completed "shortly" and a time-table for publication will follow.
Earlier this month, lawyers representing 29 families wrote to Sir John threatening legal action unless he set out a clear timetable for publication.
But he revealed today the process had thrown up additional government documents that had opened up "new issues".
Sir John said those under scrutiny had not been handed an "open-ended time-scale" and the inquiry has "remained in control of its deadlines" throughout.
Meanwhile Clare Short, the former Labour minister, has condemned the inquiry as a "very, very poor" piece of work that is "as big as War and Peace", and will find that "everyone's to blame [and] no one's to blame".
This morning it was reported the inquiry will extend blame to senior political figures outside of just Tony Blair and his then-inner circle.
Sir John will instead appropriate a higher proportion of criticism to ministers who served under the Prime Minister in 2003 than previously expected, Guardian journalists claim.
Those tipped to be under fire could include former foreign secretary Jack Straw, ex-head of MI6 Sir Richard Dearlove, and Ms Short, then international development minister.
Others in focus, the Guardian says, are Sir John Scarlett, chairman of the joint intelligence committee, Geoff Hoon, the defence secretary, and officials from two government departments.
Each person criticised by Chilcot and his four co-committee members will have to be sent draft passages of their comments, allowing them an opportunity to comment.
But this process, which has already been delayed multiple times, could drag on even further if a wider pool of people are being waited on to respond.
Blame could extend beyond ex-PM Tony Blair
It originally suffered a three-year hold-up because of a dispute between Chilcot and successive cabinet secretaries over which minutes of conversations between Tony Blair and ex-US President George W Bush could be published.
The report's publication date has been repeatedly put back even further, as its Chair insists his team need more time to allow for replies from figures criticised, even though hearings were completed back in 2011 -- the ensuing process has cost taxpayers more than £10 million to date.
David Cameron last week put pressure on Chilcot to finally deliver his findings, commenting: “It’s frustrating. We want this inquiry finished. It’s for the good of the families. It’s for the good of the country.”