The British government made selective use of intelligence to justify going to war with Iraq, two former senior Cabinet ministers told lawmakers Tuesday, the first day of a parliamentary inquiry studying the issue.

Former House of Commons leader Robin Cook (search), who quit in March to protest the government's pro-war stance, told lawmakers he feared Prime Minister Tony Blair's government had used intelligence about Iraq's chemical, biological and nuclear arms programs "to justify a policy on which we had already settled."

Clare Short (search), who also quit as international development secretary over the Iraq war, said the government exaggerated the threat posed by Saddam Hussein's weapons of mass destruction.

Cook was the first witness to appear before the House of Commons Foreign Affairs Committee's (search) inquiry into how intelligence was used in the months before the war on Iraq. The opening day of the investigation was televised live in Britain.

The lawmakers are looking into claims that Blair's government "sexed up" intelligence on Iraqi weapons of mass destruction to make a more compelling case for war.

Blair has said there is not "a shred of truth" in allegations that the government manipulated evidence about Iraq's weapons programs.

In the United States, Congress is to begin hearings into the intelligence case for war this week, but Republicans have rejected calls for a more formal inquiry.

Cook said intelligence information was a bit like "alphabet soup."

"I fear on this occasion what happened is that those bits of the alphabet that supported the case were selected," he said.

"I fear the fundamental problem is that instead of using intelligence as evidence on which to base a decision about policy, we used intelligence as the basis on which to justify a policy on which we had already settled."

Cook and Short said they had been told by security sources before the war that Saddam's weapons did not pose an immediate threat.

Short said she had seen reports from the foreign intelligence service MI6 (search) that said Iraqi scientists were still working on chemical and biological weapons programs, but did not support government claims that Saddam had weapons ready to use.

"I think that is where the falsity lies," Short said. "The exaggeration of immediacy means you cannot do things properly, and action has to be immediate."

Cook said he had received a similar briefing from MI6.

Two parliamentary committees are investigating claims that Blair's office redrafted a dossier on Iraqi weapons of mass destruction, published in September, to emphasize the claim that Iraq could fire chemical or biological weapons within 45 minutes of Saddam giving an order to do so. Intelligence officials reportedly believed the information was unreliable.

Cook said he believed Saddam "did not have an immediate threat capability" in the run-up to the war, and he doubted whether investigators would find evidence of substantial chemical and biological arms programs in Iraq.

"Such weapons require substantial industrial plant and a large work force. It is inconceivable that both could have been kept concealed for the two months we have been in occupation of Iraq," Cook said.

Over the next few weeks the committee will hear evidence from senior politicians including Foreign Secretary Jack Straw (search) — but not Blair, who said last week that neither he nor his staff would appear. Blair will give evidence to another inquiry by the Joint Intelligence Committee (search), which unlike the foreign affairs committee meets in private.

Blair has resisted calls for a full public inquiry. The threat posed by Iraq's weapons of mass destruction was the main reason given by the British government for going to war, but inspectors have found no hard evidence of chemical, biological or nuclear arms.