The British government has been strongly criticised by an all-party committee of MPs over the conduct of the British military mission in Afghanistan.
The House of Commons Foreign Affairs Select Committee says troops are being given too many tasks and lack the necessary resources to tackle the drug trade.
The report is also highly critical of the Government, saying the deployment has been undermined by unrealistic planning at senior levels, poor coordination between Whitehall departments and a failure to provide the military with clear direction.
The report says Britain should give up its lead role in tackling the drugs trade, which it says is "a poisoned chalice", given the scale of the problem, its importance to the Afghan economy and links to corruption.
The chair of the Committee Mike Gapes says British troops should focus solely on ensuring security.
Government sources said the Prime Minister had made clear the strategic focus of the mission to tackle the chain of terror stretching from Afghanistan and Pakistan to the streets of Britain.