Tony Blair has promised to make public "telling evidence" of weapons of mass destruction collated by US-led forces in Iraq.
Calls for a return for UN inspectors are growing
The prime minister told MPs that they would get an opportunity to debate the information when it was presented to them.
The prime minister's comments come just days after ex-minister Robin Cook called for the return of UN weapons inspectors to Iraq.
The UK joined the US in going to war with Iraq with the aim of ridding Saddam Hussein of its alleged weapons of mass destruction - a term which covers biological, chemical and nuclear weapons.
The apparent lack of any significant discoveries has led to increasing disquiet among Labour MPs who say they were assured the weapons were there.
The issue was raised at prime minister's questions when Mr Blair said: "We are conducting a thorough search of all potential sites for weapons of mass destruction, we are also interviewing scientists from the former Iraqi regime.
It is rather curious that they can't find these weapons
"I can assure the House [of Commons] that when we have all the evidence accumulated together - and I think people will find it is very telling evidence indeed - we will present it and there can be a proper debate about weapons of mass destruction and the Iraqi regime."
There has already been some suggestion from the government that the threat posed by Saddam was clear and did not depend on a weapons find.
Last week Commons minister John Reid pointed to the unanimous view of the security council that Saddam Hussein was guilty of defying the UN.
No Biggs thing?
The failure to find the evidence so far "no more means Saddam Hussein is innocent" than failing to find the money from the Great Train Robbery meant Ronnie Biggs was innocent, he said.
Mr Cook - who quit the government over the war - is leading calls for a return for the UN inspectors.
"We were told by President
Bush that this was a pre-emptive strike and it was necessary to get Saddam
before he hit us," he said.
"If he had anything with which to hit us, we would have found it by now. A
nuclear bomb requires a nuclear reactor. A big missile system requires a big
industrial factory. You can't hide these things.
"We were told we were going in there to disarm the weapons of mass
"If it was so compelling, so urgent, that we had to go in and disarm
these weapons that posed such a big threat to us that it justified a pre-emptive
strike, it is rather curious that they can't find these weapons.
"There is a way to square the circle and that is for the US and UK to agree
to let Hans Blix and the weapons inspectors back in again. We are refusing to do