The prospect of a "more peaceful outcome" in Iraq has grown after improvements in security conditions, the prime minister has said.
There is far less violence in Iraq, Mr Brown said
Gordon Brown said the Iraq issue had been divisive since the 2003 invasion.
But he said violence was reducing, particularly in the south where British troops are withdrawing from combat to an "overwatch" role.
The 5,500 British troops will be reduced to 2,500 in the spring and they have already pulled out of Basra.
Mr Brown told Sky News: "Yes, it has been a very divisive issue, but I do think that over the last few months Iraq has moved into a better position, at least in the south of Iraq, for us achieving a more peaceful outcome.
"While there have been huge difficulties in previous years and it is undoubtedly the case that this has divided public opinion right across the world, people are now seeing Iraq in a different position from where it was even a few months ago.
"In the south of Iraq at least, where the British troops are, there is far less violence."
The increasing role of the British troops will be training the Iraqis to maintain their own security, he said.
"I would expect in the next few months people to see some of the achievements in Iraq in a different way."
He said achievements in Iraq would be measured by maintaining better security, policed by Iraqis themselves, and seeing sustained economic development.
There are currently 5,500 troops in Iraq as part of Operation Telic.
That figure is expected to be cut by 1,000 by the end of 2007.
Since the end of the war in April 2003, troops have been helping to restore essential infrastructure and services and provide security.
UK forces are currently based at Basra airport in the south of the country.
Some 1,600 troops were withdrawn earlier in 2007 after the completion of Operation Sinbad, which was designed to put Iraqis in charge of Basra's security.
Since the invasion 173 British troops have been killed in operations in Iraq.