THE man in charge of a long-delayed report into the decision to invade Iraq had admitted he still has no idea when it will be published. The revelation came as Prime Minister David Cameron has said he is “fast losing patience” with the Chilcot Inquiry.

Yesterday morning letters between Sir John Chilcot and the Prime Minister were published on the Inquiry’s website.

Sir John’s letter apologised that the inquiry was taking so long and suggested that it was too soon to say when the report into the Iraq war would be published.

This was due, Sir John wrote, to Maxwellisation, where people who are criticised in an inquiry are given the opportunity to see that criticism and respond before the report is published.

Many of those named in Chilcot’s report had come back to him with “new issues or referred to material that was not part of the evidence submitted to the Inquiry”, which had to be “considered with care”.

Sir John also said that the Inquiry was still waiting for some responses to come back. There was no indication of who they were still waiting to hear from and how long they had been given to respond.

It was only when all responses had been received that Sir John would be able to tell the Prime Minister when he expected the report to be ready.

As much as he wanted the report to done quickly, said Sir John, it was important “to deliver a report which will do justice to the gravity of the issues we have been examining”.

It is understood that 40 people are subject to Maxwellisation, although it is not known who they are or how many have yet to respond to the Maxwellisation letters.

The Prime Minister responded to Sir John to say that the British public, and those who served in Iraq or lost loved ones in the conflict had “hoped for publication of your report by now, and we are fast losing patience”.

SNP Westminster Leader Angus Robertson raised the question during Prime Minister’s Question time.

The Moray MP asked the Chancellor George Osborne, who was standing in for Cameron, if it was true, as some media outlets were suggesting, that the inquiry had been delayed until next year.

Osborne replied that the inquiry “is completely independent of Government, and we do not determine when it publishes its conclusions”.

The Chancellor then made what he called a “broader observation” to remind the SNP of the cross-party alliance that called for the then Labour Government to set up the inquiry. If it had been set up when the SNP and the Conservatives had asked, “we would have the conclusions now” said Osborne.

Osborne and Cameron, Robertson reminded the Chancellor, had both “voted for the war that we were led into by the then Labour Government”

The Inquiry was initially set up in 2009 to look at the UK’s involvement in the Iraq war and discover, “what happened” and “to identify the lessons that can be learned”.

In those six years, the inquiry has now cost in excess of £10 million, roughly £1.4m in the last year.

Sir John and his committee have taken evidence from defence chiefs, ministers and former Prime Ministers Tony Blair and Gordon Brown.

Speaking after PMQs, Robertson said: “The Iraq war was a foreign policy disaster and the ramifications are still being felt today.

“I asked the Chancellor if he felt a moral and political responsibility for getting to the bottom of this calamitous war and its consequences.

“This inquiry needs to be published in full – and as a matter of urgency. Abandoning it would be wholly unacceptable.

“Answers are long overdue, and the continued delays to the publication of this report are a democratic outrage.”