The next head of the British army says Britain may have to retain a presence in Afghanistan for up to 40 more years.
General Sir David Richards says he believes the commitment will have to continue even after United Kingdom troops are no longer needed.
The general, who takes over on 28 August, told The Times that "nation-building" would last decades.
He saud troops will be required for the medium term only, but Britain will continue to play a role in "development, governance [and] security sector reform."
Shadow defence minister Gerald Howarth said Britain has to be there long-term to achieve its objectives.
General Richards commanded 35,000 troops from 37 nations when he was head of NATO forces in Afghanistan between May 2006 - February 2007.
He said he strongly believed the campaign was "winnable", but added it would take "a long time and considerable investment".
General Richards added: "We must remember, though, that we are not trying to turn Afghanistan into Switzerland."
The BBC reports 195 British troops have been killed in Afghanistan since 2001.
