BARELY a week goes by in politics without ­someone testily demanding an official inquiry into this or that passing hiccup, requests that can be fairly tossed aside by Government ministers.

But the 2003 Iraq war was never part of the usual parliamentary swings and roundabouts.

If any event in recent political life merits a full and forensic inquiry, it is then-prime minister Tony Blair's decision to take the country to war in an unholy alliance with then-US president George W Bush.

That decision - promoted on the false premise that Saddam Hussein not only possessed weapons of mass destruction but was also ready to use them against British interests at 45 minutes' notice - was the bloodiest mistake in modern UK foreign policy.

It shattered trust in the UK and the US overseas. It left tens of ­thousands of Iraqi civilians dead, and a ­country too weak to resist the rise of the jihadist Islamic State (IS) group. Fêted abroad, Blair has become a pariah at home.

More than a decade since the invasion, Iraq was even one of the threads running through the Scottish independence referendum - and issue cited by many Yes supporters and former Labour voters as a key reason for wanting to break with Westminster.

How extraordinary and ­intolerable, therefore, that the official report on the war remains unpublished more than five years after Sir John Chilcot's inquiry into it was first announced.

The fault lies not with Chilcot but with his nervous subjects. ­Whitehall officials have argued against ­releasing more than "the gist" of the discussions between Blair and Bush, for fearing of upsetting the UK's special relationship with America.

Expected to face criticism, Blair, former foreign secretary Jack Straw and Government legal personnel also have reason to drag out the current final stage, during which they are allowed a chance to respond.

For a while, it appeared David Cameron was on the side of the angels, voicing his hope last year that the report would be out by Christmas. However, he now seems part of the problem.

Last month, after the US Senate published its chilling account of CIA abuses after the attacks of ­September 11, 2001, Cameron threw up his hands in despair on Chilcot.

He said: "I am not in control of when this report is published. It is very important in our system that these sort of reports are not controlled or timed by the Government."

But earlier this month in the House of Lords, the Cabinet Office minister Lord Wallace of Saltaire flatly contradicted Cameron.

Wallace said that, although it was a matter for Chilcot to decide when to submit his finished report to Downing Street, it was then up to the Government to decide when to publish it.

"The Government have committed that if the report is not available for publication by the end of February, it will be held back until after the election," he said, as a lengthy period would be needed to digest and debate the report.

In the same Lords exchange, the Liberal Democrat peer Lord Dykes called the delay an "utter and total disgrace" while the Conservative former home secretary Lord Hurd said it was "becoming a scandal". We agree.

Rather than an excuse for yet more delay, the election ought to act as a spur to publication. If Cameron receives the report before May, it ought to be published so voters can take account of it.

This newspaper's opposition to the Iraq war, and the flawed ­decision-making process that led to the invasion with the US, is well known. That there were failures is also beyond dispute.

The invaluable purpose of the Chilcot report is to show what went wrong and help avoid any repetition.

The First Minister's call for a cross-party consensus on publication before the election - although partly aimed at discomforting Labour leader and Iraq war supporter Jim Murphy - is to be welcomed, as is every push for publication.

The issue also underlines the need for a swifter system of inquiries to ensure public confidence in the democratic process.

In that same Lords exchange, Lord Wallace said the Chilcot report delay was "not unusual for inquiries of this sort", and noted two ­investigations into alleged abuse by British soldiers in Iraq - the al-Sweady and Baha Mousa inquiries - took five years and three years and cost £24 million and £13.5m respectively.

But that is no reason to shrug off the Chilcot delay - 12 years on, the demand for answers on Iraq is as urgent and insistent as ever.