LONDON: Former British prime minister Tony Blair faces a public grilling Friday over his decision to wage war on Iraq, seven years after a bloody conflict that still divides his country.

Blair is the star witness in a long-awaited inquiry that commentators hope will finally resolve questions about the intelligence that justified the March 2003 invasion, and whether the US-led war was legal.

Anti-war campaigners, who held a million-strong march against the invasion at the time, have promised protests for the hearing in London, while the public interest is such that organisers had to hold a ballot for spectators.

Relatives of some of the 179 British soldiers who died in the war will also be there, many of them keen to confront the man they hold responsible.

Britain and the United States justified the invasion of Iraq with the threat posed by its possession of weapons of mass destruction (WMD) in defiance of United Nations resolutions, but they did not have explicit UN approval.

Concerns this meant the war was illegal were compounded by the failure to find the WMD, raising questions about the reasons for the conflict.

The inquiry panel, led by former top civil servant John Chilcot, has the remit of learning lessons but not apportioning blame, and the focus has inevitably narrowed onto Blair.

Although he is Labour's most successful prime minister, leading the party to three successive electoral victories, Blair's strong support for such an unpopular war contributed to his decision to step down early in June 2007.

Blair has always insisted the war was legal -- supported by his then attorney general, Peter Goldsmith, who gave evidence here Wednesday -- and said he was convinced Iraq had chemical and biological weapons.

However, the ex-prime minister has never shaken off accusations that he and then US president George W. Bush were determined to remove Saddam Hussein by any means possible -- and that the intelligence was doctored to support their case.

Successive government officials and ministers from the time have told the inquiry that the intelligence pointing to the WMD was patchy at best, and several made no secret of their desire to see Saddam removed from power.

Blair himself told the BBC last month that he would "still have thought it right to remove" Saddam because of the threat he posed to the region, although he acknowledged they would have had to deploy "different arguments".

One of the key documents in the intelligence case against Saddam was a September 2002 dossier in which Blair wrote, in a foreword, that Saddam's possession of WMD was "beyond doubt" and he could deploy them within 45 minutes.

The government argued that its legal basis for invading Iraq came from UN resolution 1441, passed in November 2002, which demanded Saddam disarm.

However, the Foreign Office's own lawyers at the time told the inquiry that a second UN resolution explicitly condemning Saddam for not cooperating with weapons inspectors would have been needed to make military action legal.