"As security forces build up, that will lead to a draw-down of British troops," William Patey said.

"British troops will stay here as long as needed and wanted by the Iraq government and no longer."

"There is no timetable," Patey said. "It will be when conditions are right."

On Tuesday, British Air Marshal Glenn Torpy was quoted in London's Daily Telegraph as saying troops would decrease gradually in "battalion(-sized) chunks" following the next Iraqi elections, expected at the end of the year.

As troops draw down in Iraq, Britain is likely to increase its 1,000-strong force in Afghanistan, backed by Royal Air Force Harrier jets, to fight remnants of the Taliban, Torpy said.

The United States, backed by Britain and other allies, launched a war against the Islamist Taliban and Osama bin Laden's Al-Qaeda network in the wake of the September 11, 2001 attacks in New York and Washington.