Sir John Chilcot should set out a timetable for publishing his long-awaited report on the Iraq War "pretty soon", David Cameron has demanded in a sign of his growing frustration at the delays in the process.
The Prime Minister said the families of soldiers who lost their lives in the conflict had a right to expect the inquiry to "get on with this".
Although the Prime Minister wants a timetable for the report to be published to be set out by Sir John as soon as possible, Whitehall sources do not expect this to happen before Parliament returns in September.
The Prime Minister said members of the public "deserve" the timetable so they can be assured progress is being made.
Mr Cameron said: "Right now I want a timetable. More important than anything is thinking of the parents who lost loved ones in Iraq.
"The most powerful conversation I've had about this was a mother who said to me at the Staffordshire Arboretum, when we were commemorating the Bastion Memorial Wall for Afghanistan, (it) was just - you know - it's the parents and the families who want answers.
"And for their sake, as well as for the sake of the public, we've got to get on with this. I can't make it go faster because it's a public inquiry and it's independent, but I do want a timetable and I think we deserve one pretty soon."
Sir John insisted in July that his inquiry was making "significant progress", although he could not set a date of the publication of his findings.
He said officials were continuing to work through the so-called "Maxwellisation" process of assessing responses from individuals facing possible criticism in the final report.
He played down a claim by Cabinet Secretary Sir Jeremy Heywood that he had turned down repeated offers of assistance to speed up the publication.
In a letter to the Commons Foreign Affairs Committee, Sir John said inquiry officials had had a "constructive discussion" about the additional assistance the inquiry would need in its final stages.
The continuing delays to the inquiry - which was launched in 2009 - has caused exasperation among MPs with Mr Cameron warning last month that he was "fast losing patience" over the lack of progress.