Sir John set to call Blair and Brown as witnesses

Tony Blair and Gordon Brown are set to be called to give evidence in public to the Iraq inquiry, it emerged last night.

Sir John Chilcot, who is heading the investigation, told opposition leaders he intended to summon all those who had made key decisions with regard to the invasion of Iraq. They will include the former prime minister and almost certainly Mr Brown, who as chancellor sanctioned spending on the invasion.

They are likely to appear later this year or early in 2010, just months before the expected date of the general election. Others certain to be summoned include Jack Straw, who was foreign secretary, and Lord Goldsmith, the former Attorney General.

Sir John re-assured Tory leader David Cameron and Liberal Democrat leader Nick Clegg that hearings would be held in public unless there were "compelling reasons" not to do so. He has agreed to look into alternatives to putting witnesses under oath, which is impossible as the proceedings will not form a full-scale judicial inquiry.

In a letter to Sir John, Mr Clegg said: "It was... good to hear you confirm that you will be seeking evidence from Tony Blair and others in high office at the time, and would want their evidence to be held in public except in very limited circumstances."

Mr Cameron said Sir John had told him the present membership of the inquiry team was too narrow.