London: Britain plans to substantially scale back its troop numbers in Iraqi during 2009, the head of the country's armed forces said.

Air Chief Marshal Jock Stirrup said the UK will withdraw soldiers to help ease major strains on Britain's military, which has been stretched by deployments in both Afghanistan and southern Iraq.

Britain had planned to cut its number of troops in Iraq from 4,000 to 2,500 earlier this year, but postponed the withdrawal in March amid a spike in militia violence.

"I would expect us to see further substantial progress towards a more sustainable tempo in the course of the next year," Stirrup told BBC television, referring to lowering troop numbers in Iraq.

Britain has increased to almost 8,000 its number of troops in Afghanistan and Stirrup said the UK military does not have the capacity to keep soldiers deployed across both fronts for much longer.