Tony Blair is to be recalled before the Iraq inquiry to answer questions over whether he pressured his Attorney-General to change his advice on the legality of the war.
The former British Prime Minister will face a second session before the Chilcot inquiry in the new year - a year after he refused to express regrets over leading Britain to war in 2003.
His statement provoked fury in the hearing, with members of the audience calling him a "liar" and a "murderer".
The decision to summon him back will be a blow to Blair, who had hoped his previous six-hour appearance would defuse the continuing controversy over the war.
But it is evidence that the Chilcot team believes there are still significant gaps to be filled as they try to piece together a full picture of the build-up to war. They are preparing to question him over suggestions that he put pressure on Lord Goldsmith, who was then the Attorney-General, to alter his advice on the legality of the war.
The lawyer's change of heart just before the planned invasion gave a green light for British troops to join the United States-led military action.
Blair has denied attempting to influence Goldsmith, but previously classified papers showed he queried the Attorney-General's previous view that invasion without a new United Nations resolution would be illegal.
He is also likely to face fresh cross-examination over the commitments he gave to former US President George W. Bush that Britain would back an invasion, as well as questions on weapons of mass destruction and whether he allowed proper debate in the Cabinet on the war.
Goldsmith has been asked to provide further written evidence to the inquiry, which will hold its new round of public hearings in January and February.