The British Army operating in Afghanistan could stay in the region for five more years, according to General David Richards.
Richards said the reason the UK had no more than 10,000 troops in Afghanistan was that it could "endure that forever" within the army's deployable strength of 75,000, according to Reuters.
"I'm assuming we'll be involved in Afghanistan for another three to five years, that is the current working assumption at the Ministry of Defence," he said.
UK Prime Minister David Cameron has ordered UK forces to not to stay in the region longer than necessary and ruled out sending more troops to the Afghan mission.
Since 2001, a total of 300 UK military personnel have died on operations in the southern province of Helmand.
The US is expected to gradually withdraw the troops from July 2011 as Afghan forces take the lead to maintain security in the country.