Gordon Brown is facing questions at the Iraq inquiry and is likely to be pressed on the issue of whether he was responsible for putting lives at risk by cutting military budgets.

He has maintained that it was right to take military action in 2003, and that while the battle was won in seven days, it took a further seven years to win the peace.

The Prime Minister is expected to be asked to respond to claims that he "guillotined" the military budget while he was chancellor, forcing helicopter and warship projects to be axed. The inquiry has already heard from defence chiefs and ministers who complained that the Treasury imposed swingeing cuts after the Iraq invasion in March 2003.

General Lord Walker of Aldringham, the former head of the armed forces, revealed that all of Britain's top military chiefs threatened to resign in protest at the moves. He said the top brass "drew a line" halfway down a list of projects facing the axe and warned Treasury officials to go no further.

Sir Kevin Tebbit, the former top civil servant at the Ministry of Defence (MoD), said he was running a "crisis budget" during this period. The problem arose when the Treasury realised that new Whitehall accounting rules introduced in 2002 to drive down costs had actually allowed the MoD to increase spending.

Sir Kevin told the inquiry: "By the summer of 2003 the Treasury felt that we were using far too much cash. And in September 2003, the chancellor of the day (Mr Brown) instituted a complete guillotine on our settlement."

As a result the MoD had to cut projects including helicopters, Nimrod spy planes, Royal Navy destroyers and submarines, artillery and Challenger tanks, as well as reducing numbers of troops and civil servants. Former defence secretary Geoff Hoon earlier told the inquiry there was a strong belief within the MoD that the Treasury had never properly funded the 1998 strategic defence review.

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He also said budget cuts meant defence chiefs were forced to cancel orders for extra helicopters which could have been used in current operations in Afghanistan. After these claims emerged, Mr Brown insisted he had always taken seriously the need to fund the armed forces properly.

A top civil servant at the Treasury, meanwhile, told the inquiry in January that nobody from the MoD complained about funding in the run-up to the Iraq War. Sir Nicholas Macpherson also said none of the requests for essential military equipment for the invasion - referred to as urgent operational requirements - were turned down.

Another issue the five Iraq Inquiry panel members are expected to ask Mr Brown about is how closely involved he was in the decision to go to war. Alastair Campbell, the former No 10 communications director, told the inquiry he was one of the inner circle of "key ministers" consulted by Tony Blair in the build-up to the invasion.

But former international development secretary Clare Short said the then-chancellor was "marginalised" and even feared he would be pushed out of the Cabinet. Anti-war protesters have announced they will try to hand over a giant "bloodstained" cheque to the Prime Minister when he appears before the inquiry.

The Stop the War Coalition said the cheque, made out for £8.5billion, was aimed at highlighting the Mr Brown's role in the "illegal and unjustified" war.