The families of the 179 British troops who lost their lives in the Iraq war have found delays to the Chilcott Inquiry report deeply distressing.
ITV News correspondent Dan Rivers spoke to Reg Keys, who lost his son Tom during the conflict, about his wait for answers:
Roger Bacon, who lost his son Matthew in 2005 during the Iraq conflict, said he is desperate for answers about why the UK went to war.Read the full story ›
Political leaders and the parents of the casualties of the 2003 war have been united in their anger and frustration at further delays to the publication of the Chilcot Iraq War report.
The report is apparently being held up because not everyone implicated in it has had their right to reply but Former Prime Minister Tony Blair, who backed George W Bush and took Britain to war, insisted the delay was not because of him.
ITV News' Political Editor Tom Bradby reports:
A spokeswoman for the Iraq War inquiry has confirmed that Sir John Chilcot received the invitation to appear before the Foreign Affairs Select Committee and was considering his response.
Chairman of the Committee, Sir Richard Ottaway, has written to Sir John asking him to face MPs "at some point in the next two weeks" to explain "what stage preparation of the report has reached and what obstacles remain" before it can be submitted.
The father of a soldier killed in Iraq has told ITV News he is "absolutely disgusted" by the latest delay in publishing the inquiry report into the war.
Roger Bacon, whose son, Major Matthew Bacon, was killed in Basra in 2005, said the families of fallen servicemen needed answers from Sir John Chilcot's panel.
"I'm absolutely disgusted by it. By the time this inquiry is published, it will probably have taken longer than the whole of the Iraq war - that's absolutely ridiculous," Mr Bacon told Mary Nightingale.
Delays to the publication of the Chilcot Inquiry are not down to senior politicians trying to "dodge" criticism, David Cameron has said amid growing anger.
The Prime Minister said there was "no mystery" behind Sir John Chilcot's announcement that his panel's findings would not be published before May's general election.
"My understanding is that there is no mystery in why this is taking so long," Mr Cameron said.
"It is a very thorough report and you have to give the people who are criticised in a report the opportunity to respond to all those criticisms.
"That is what is happening at the moment. I don't believe, from what I understand, that anyone is trying to dodge this report or put off this report."
Tony Blair has denied suggestions that he has caused the delay in the publication of the Chilcot report.
A spokesperson for Mr Blair said the former prime minister "regrets" the delay and wanted the inquiry to be allowed to proceed with its work.
We have repeatedly said that it is not true to say that Tony Blair has caused the delay in the report’s publication.
Sir John’s letter makes reference to notes and records concerning Mr Blair, which some may interpret as an implicit suggestion that Mr Blair caused the delay, this is not true.
On the contrary, he regrets this delay in its publication.
Incorrect allegations and politically motivated speculation do nothing to shine a light on the issues involved.
It is an independent inquiry and it should be allowed to proceed with its work.
David Cameron has said Ed Miliband should be "recognising his own regret" as he blamed Labour for delays in setting up the Chilcot inquiry.
The Prime Minister said the report, which has been delayed until after May's general election, would have been published "years ago" if it was not for Labour's opposition.
"We want to see this Iraq inquiry published promptly but if everyone in this house including members opposite had voted to set up the inquiry when we proposed it would have been published years ago," Mr Cameron said.
"So perhaps he can start by recognising his own regret at voting against the establishment of the inquiry.
"He voted again and again against establishing the inquiry and as ever no apology."
Ed Miliband said: "It was set up six years ago and I agree with Prime Minister it should be published as soon as possible."
Nigel Farage has said the decision to delay the release of the Chilcot report until after the general election "smacks of an establishment cover-up".
"It beggars belief that here we are, four years after the end of the Chilcot Inquiry, still waiting for the report," the Ukip leader said.
"It smacks of an establishment cover-up, and one which I suggest the British public will see right through."
Mr Farage's party is urging people to sign an online petition calling on the Government to release the report before the election.
David Cameron has said he would have liked to have seen the Chilcot report published "well before" the general election after the chair of the inquiry confirmed it would not be published for "some further months".
Mr Cameron said he hoped it will be possible to publish it "shortly thereafter".
"I would have liked to have seen your report published already and certainly well before the forthcoming election," the Prime Minister said.
He also criticised the previous Labour government saying, "had the previous Government established this inquiry when I first called for it, we would not be in this position today".