John Cecil left behind a daughter and two stepchildren

Ann Nichol lost her son John Cecil, 36, when the Sea King helicopter he was travelling in crashed during the first few days of the war.

Colour Sergeant Cecil was one of eight personnel from Plymouth-based 3 Commando Brigade who died in the crash in Kuwait.

Mrs Nichol, 58, of Gateshead, Tyne and Wear, reacted angrily to US Defence Secretary Donald Rumsfeld's admission that the weapons may never be found.

She said: "If this turns out to be a lie then Tony Blair should resign and he should be prosecuted under international law as a war criminal.

We didn't fight this war for just reasons as there wasn't any threat to the UK from Saddam Hussein Ann Nichol

"If they don't find any weapons of mass destruction then this war has been based on lies and they have put the lives of all our sons and daughters on the line for nothing."

Mr Blair is facing mounting pressure over the issue of whether Saddam Hussein had had nuclear, chemical or biological weapons

No physical evidence of weapons of mass destruction has been found so far in Iraq.

The prime minister has continued to defend his position and has called for patience as the hunt for the weapons continues.

Mrs Nichol said: "We didn't fight this war for just reasons as there wasn't any threat to the UK from Saddam Hussein."