Leading article: This inquiry into the invasion of Iraq needs to be open

Yesterday was a significant moment in British politics; but not as significant as it ought to have been. Six years and three months after British troops entered Iraq as part of a US-led invasion force, the Prime Minister announced that there is, at long last, to be an independent investigation into the most controversial British military engagement since the Suez crisis.

The Government had previously refused to establish an inquiry into the Iraq invasion arguing that it would be inappropriate to conduct such an inquest while our troops were still serving in Iraq. But the lowering of the Union flag at the British Army's Basra base two months ago put to rest that unconvincing excuse for inaction.

There are elements to Gordon Brown's statement yesterday that deserve to be welcomed. The timeframe for the inquiry (going back to the summer of 2001) should be sufficiently broad to cover all the contentious issues leading up to the invasion. Some key questions, particularly relating to the crucial pre-March 2003 period need to be answered. Was the diplomatic alternative to military action shut down prematurely? Did the Government distort the security intelligence it received regarding Iraq's weaponry? And precisely what advice did the Cabinet receive, and when, regarding the legality of the prospective invasion?

Whatever one's view of the wisdom of the military operation, these remain legitimate questions. There will be those who argue that they have been adequately addressed by the Hutton and Butler inquiries. But the first of these was tasked with looking specifically into the death of the Ministry of Defence scientist David Kelly. The second focused on the failings of the intelligence services, rather than the role of the Government. And neither provided the comprehensive and forensic evaluation of the build-up to the conflict that is needed.

The choice of Sir John Chilcot, an individual who enjoys no great reputation for independence, to chair the inquiry is disappointing. But Mr Brown is surely right to appoint non-partisan figures to the panel. The passions aroused by the invasion are, regretfully, still run too high to hold a cross-party inquest. It is disappointing too that the inquiry will not report until well into next year, although we should be pleased we are not facing an open-ended investigation along the lines of the Bloody Sunday inquiry. But the most disappointing and unsupportable aspect of yesterday's statement is that that the inquiry is to be held behind closed doors. Mr Brown offered the argument yesterday that national security would be jeopardised by making the proceedings public. But that will not wash. The Hutton inquiry provides a clear recent example of a public inquiry which took evidence from high-ranking members of the intelligence services and yet whose proceedings were fully open to the public and media. When Sir Richard Dearlove, the head of MI6, gave testimony to Lord Hutton he did so through an audio link. This is no reason why the same kind of safeguards should not be applied once again.

The Government's decision to throw a veil over the proceedings of this inquiry sends the dangerous message that this exercise is less about learning lessons from the invasion of Iraq than smothering past mistakes. The Prime Minister made the first tentative step towards open government yesterday by establishing this investigation. Now he needs to follow his arguments through to their natural conclusion by requiring the inquiry to produce interim reports and to conduct its proceedings in the clear light of day.