Prime Minister Tony Blair has denied reports that British soldiers will start withdrawing from Iraq next May.
The government has denied troops will begin leaving Iraq in May
Any exit strategy "depends on the job being done", he told BBC's Sunday AM.
However, Defence Secretary John Reid has hinted the handover to Iraqi forces - followed by the gradual withdrawal of UK troops - could begin next year.
Mr Blair also said he had not expected the "ferocity" with which elements in the Middle East would try to disrupt the political process.
But he said despite insurgents infiltrating the Iraqi police force and the escalating violence in the country, he would have made the same decision to invade Iraq.
"There is no doubt in my mind at all that what is happening in Iraq now is crucial for the future of our own security, never mind the security of Iraq or the greater Middle East," he added.
He said the strategy for withdrawal had always been to "retire as the Iraqi capability builds up".
Reports in the Observer newspaper suggested that Britain had already "privately" informed Japan of its plans to begin withdrawing from southern Iraq next May.
But Mr Blair insisted: "What we do depends on the job being done. There is no arbitrary date that's being set and the allies are all in exactly the same position.
"Our mandate there from the UN is to stay there for as long as the Iraqi government want us and as long as it takes to build up the capability of the Iraqi forces."
A separate debate on the Iraq war and its aftermath is unlikely to make it on to the Labour Party conference agenda, as not enough constituencies have put forward motions on the issue.
On the first day of the conference in Brighton, a critical motion calling for the withdrawal of British troops before the end of the year was ruled out of order.
Basra situation 'difficult'
Mr Blair said he would "absolutely not" accept an arrest warrant from a Basra judge for two British soldiers after an Iraqi civilian was reportedly killed and a police officer injured.
The two servicemen - believed to be undercover SAS officers - were detained after a confrontation on Monday and later freed by UK troops who stormed a police station in the southern Iraqi city.
Mr Blair said: "The Iraqi government are not asking us to apologise. We will do anything that is necessary to protect our troops in any situation. I know it has been difficult in Basra."
The Observer suggests detailed plans on troop withdrawal are being drawn up by UK, US and Iraqi officials and will be presented to the Iraqi parliament next month.
It quotes military sources as saying the document would lay out a detailed exit "road map" by multinational forces.
Defence Secretary John Reid denied there was any such plan but told Sky News' Sunday with Adam Boulton: "In the course of next year, there could be the start of the process of the handover to the Iraqis."
When counter-terrorism operations had been handed over, Mr Reid said, "There will then be a process - it won't happen overnight - where they gradually take the lead, we gradually withdraw to barracks and we gradually withdraw from Iraq itself."
Tory leader Michael Howard told the same programme: "I think that if we were to leave prematurely we would leave behind a country that would be in danger of becoming a real hotbed of international terrorism and that would be a disaster.
"So we must do what we set out to do - we must continue to work towards the achievement of a stable, sustainable and peaceful Iraq."