The Iraq debate exposed differences of opinion between MPs and peers of all parties - and reflected the divisions present across the country as a whole.

In the House of Commons many MPs appeared resigned to the onset of war.

In a debate in which the House heard from 55 MPs, Labour's Steven McCabe insisted he was "no fan of military action at all".

"But I do think there does come a time where if there is any justification in anything we say then the line must be drawn and the point must come when it is abundantly clear that the talking is over and the intent is real," he told the Commons.

Foreign affairs committee chairman Donald Anderson said he recognised "the uncertainties and the high risks" of war against Iraq.

"I share many of the suspicions of colleagues of the unilateralism of the US administration but I am confident that the French position can only encourage that unilateralism," he added.

Former shadow Northern Ireland secretary Andrew Mackay said the conduct of the French government had been "nothing short of disgraceful".

But many MPs said they approached the vote with a "heavy heart".

Speaking just an hour before the division, Labour's Lindsay Hoyle said he was still grappling with his conscience.

He told MPs he would listen to the debate "right up to the wire" before determining how he would cast his vote.

But other MPs were not set to slide into war without registering their protest.

John Denham, who resigned from the Home Office in order to vote against his government, said the current approach had a "real cost and a real danger".

"It undermines the legitimacy we must maintain to tackle the many threats to global security. It fuels the movements that are antipathetic to our values and way of life," he said.

Clive Efford said there was more than a whiff of "double standards" in the approach being adopted by Britain and the US.

Fellow Labour MP Brian Sedgemore said the prime minister had shown "enormous" misjudgement over Iraq.

In a sideswipe at Clare Short - who announced she is to stay in government despite serious concerns about war - Tony Banks said "my decision tonight will not involve wrestling with my conscience all night... then clinging onto office".

Lib Dem MP David Heath spoke for his party when he said the "case for war had not been made... to my satisfaction".

And he warned that the international community was entering a "100 years war".

Left-winger Bob Marshall-Andrews said the public were aghast at the prospect of Saddam Hussein being allowed to flee into exile.

"We are now in a black period of American history. That is what is perceived darkly by our constituents," he told the House.

The DUP's Iain Paisley, however, said MPs had a duty to support British troops "all the way".

Former Tory chairman Sir Brian Mawhinney said the issue was "not a debate about how much legality there is on one side and how much morality there is on another".

"I am just a simple Belfast boy and to me it is whether or not we have the will to do what we believe and know to be right after having prevaricated for a long time," he told the House.

But Billericay MP John Baron, who had earlier resigned from the opposition frontbench, said that to "wage war now makes little sense".

"Until we know that all other avenues have been exhausted our consciences cannot be at ease," he warned.

In the House of Lords, peers also expressed reservations about the move to war.

Field Marshal Lord Bramall, a former chief of the defence staff, told his colleagues in the Lords debate that the West hadn't "been in as big a muddle over our international relations since the Suez crisis".

But he still believed war was the only option left open to Britain and the US.

"Shoulder to shoulder, my Lords, it must be. And we can only hope that the optimistic forecasts of how long the war will last will prove accurate," he said.

Former Cabinet minister Baroness Williams, speaking for the Lib Dems, said war was "always a catastrophe".

"Its course is unpredictable. No one can say what the effects of the imminent war on Iraq will be," she said.

But echoing the remarks of the prime minister, the leader of the House, Lord Williams of Mostyn, warned of the risks of inaction.

Given the divisions in the House of Commons, he said the upper house had to "hold firm" behind the prime minister.

"The country and this parliament each reflects the other. The debate as time has gone by has become less bitter but not less grave," he told the chamber.

"It matters because the outcome of these issues which we are facing with such imminence will determine more than the fate of the present regime in Iraq.

"It will determine more than the future of the unfortunate people of Iraq.

"It will actually determine the way Britain and the world confront the central security threat of the 21st century."