Tony Blair is facing calls to make a statement to parliament on Iraq and the murder of British hostage Ken Bigley.

With MPs returning to Westminster today after the conference recess, Labour MPs, who will meet the prime minister tonight, are also set to renew calls for a Commons debate.

Hans Blix, the former UN weapons inspector, said on Sunday that Blair was "clinging to straws" to justify the war.

The Iraq Survey Group reported last week that Saddam Hussein had no weapons of mass destruction.

It has emerged that Ken Bigley begged the prime minister and the British people to save his life moments before he was beheaded.

In a video posted on the internet yesterday, Bigley was shown kneeling before his captors.

He said: "Here I am again, Mr Blair and your government, very, very close to the end of my life.

"You don’t appear to have done anything to help. I’m not a difficult person. I am a simple man who just wants to live a simple life with his family.

"These people, their patience is wearing very, very thin and they are very serious people.

"Please, please give them what they require, the freedom of the women in Abu Ghraib. If you do this the problem is solved.

"To the British people: more than ever, I need your help, more than ever I need your voices, to go out into the streets and demand a better life for the females who are in prison in Abu Ghraib prison in Baghdad.

"I can’t say a great deal more, I’ve said so many things to you at so many different times. All I can tell you now is that we have very short time left now."

Immediately after he spoke, the masked man standing behind him read a statement denouncing the government before beheading the hostage.