Defence Secretary Michael Fallon last night urged Sir John Chilcot to end the suffering of grieving families by finally publishing his long-overdue report into the Iraq war.

He became the latest figure to call for an end to delays that the relatives of troops say is preventing them getting to the truth.

Mr Fallon said the examination of the reasons why Britain took part in the disastrous 2003 invasion at the cost of 179 UK lives should be published ‘without further delay’.

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Defence Secretary Michael Fallon (left) has urged Sir John Chilcot (right) to end the suffering of grieving families by finally publishing his long-overdue report into the Iraq war which has already taken six years

His intervention came after 29 families took unprecedented legal action in a bid to force Sir John to deliver his report – which has taken six years and £10million of taxpayers’ money – by December.

The delays have been blamed on the controversial process of ‘Maxwellisation’, in which those who are criticised in the report – expected to include Tony Blair – are notified and allowed to respond before publication.

Mr Fallon said: ‘This report has been delayed long enough. I share the deep frustration felt by bereaved families and those who served at the way this ‘Maxwellisation’ process has held up publication.

'The inquiry should be in no doubt that the families, the wider public, and the Government now want this report published without further delay.’

Inquiry chairman Sir John has not been seen since the Daily Mail revealed how families had given him a two-week ultimatum to set a date for releasing the report or they will fight him in the courts.

Families believe his decision not to set a timetable for publication is unlawful because inquiries should be concluded in a ‘reasonable time frame’.

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They are preparing to launch a judicial review if the 76-year-old fails to respond. Relatives are seeking a face-to-face meeting with Sir John to discuss their concerns but they believe the career civil servant is unlikely to agree.

Rose Gentle, whose 19-year-old son Gordon was killed in Iraq in 2004, said: ‘Why is he hiding?

‘Is he embarrassed that the families are now starting to speak about the delays to the report? We would like answers but he is not treating us with any respect whatsoever.’

Matthew Jury of McCue & Partners solicitors, which is representing relatives, said: ‘The families suffered when their loved ones died, they’ve suffered due to unnecessary and seemingly cynical delays, which have kept them from knowing why they went to war, and now they are suffering Sir John’s silence while he refuses to even acknowledge, let alone answer, their questions.

‘How much do they have to endure before this report is finally published?’

Last week Sir John was accused by senior MPs of lacking a conscience for failing to give bereaved families the answers they had been promised.

Despite the clamour, the inquiry chairman was recently working just eight hours a week. He is now understood to be on holiday.

Fury is mounting over the snail’s pace of the inquiry, which began in 2009 and finished taking its main evidence in 2011. This week it will have taken longer than the six years and 69 days that UK troops fought in Iraq.

Sir Richard Ottaway, former Tory chairman of the Commons’ foreign affairs select committee, said: ‘[What Sir John] should be saying to people... is, “Here is the deadline. I’m going to make my decision about what you’re saying by the end of September and I’m going to publish by the end of the year”.’

Ministers have admitted they cannot order the retired civil servant to deliver his report because the inquiry was independent.

An Iraq inquiry spokesman said: ‘We intend to complete our task as quickly as possible... to ensure we deliver a report which will do justice to the gravity of the issues we have been examining.’