His comments are seen as most clear signals from the UK Government about the troops" stay in strife-torn Afghanistan. Last month, during his visit to Kabul, British Prime Minister Gordon Brown had said that pledged his troops" support for "next five years", but impressions were drawn that they could remain there for at least a decade.
Replying to a question as to when troops would be pulled out of Afghanistan, Browne said: "We cannot risk it again becoming an ungoverned training haven for terrorists who threaten the UK. But there is only so much our forces can achieve. The job can only be completed by the international community working with the Afghan government and its army. It is a commitment which could last decades, although it will reduce over time."
Military figures in Afghanistan have already suggested that the efforts there will take decades, while ministers have only stressed the "long-term" nature of the commitment.
A MoD spokeswoman had said that the UK"s role in Afghanistan would evolve over time. "The British government"s commitment to Afghanistan is long-term and it"s not just a military commitment," she said adding "Previously it was a failed state and it"s going to be a long-term commitment to make sure it"s a stable country."