Labour MP challenges Blair

Brian Donohoe said the prime minister must deliver

The prime minister must find evidence of weapons of mass destruction (WMD) in Iraq or be forced to resign, according to a Scottish MP.

Cunninghame South MP Brian Donohoe said Tony Blair must unearth evidence or his position will become untenable.

The MP said it has yet to be proved that Saddam Hussein posed an imminent chemical or biological threat.

Mr Blair said earlier this week he believed "concrete evidence" of WMD will be found.

We have to go back to the stages where we looked at the reasons for us to go to war Brian Donohoe MP

Speaking on BBC Radio Scotland, Mr Donohoe said the reason given for war in Iraq was the imminent threat posed by WMD.

He said: "If I don't see the evidence that's overwhelming in terms of the weapons of mass destruction having been there, I'm not going to call, but I do believe that the position of the prime minister in these circumstances is untenable and that he would have to resign.

"We have to go back to the stages where we looked at the reasons for us to go to war.

"And the only thing that convinced me and convinced many others was the fact that we were going to war because of the immediate threat of Saddam by utilising weapons of mass destruction."

Mr Donohoe said if this proved not to be the case then there was "no legitimate reason for us to go to war".

Tony Blair is adamant weapons will be found

Responding to BBC political editor Andrew Marr's assertion that senior Whitehall sources had ruled out finding weapons in Iraq, the MP said he "wanted to hear it from the horse's mouth".

The BBC's political editor said the sources believe weapons did exist - but were hidden or destroyed by Saddam Hussein before the war.

Mr Donohoe said: "I want to hear it from the prime minister and we need a statement from him at some point to indicate what the position is."

The MP said backbenchers would not be impressed if the prime minister said he only expected to find evidence of WMD.

In a brief statement, a Scottish Labour Party spokesman said: "The prime minister believes evidence of Saddam Hussein's weapons programme will be found."