Britain must continue to work with international intelligence agencies in the fight against terrorism even if they do not share UK standards on human rights, the Foreign Office warned today.
In its annual report on human rights around the world, the Foreign Office said the UK could not afford the "luxury" of co-operating only with agencies in countries which did not abuse or torture detainees.
It said British agencies tried to minimise the risk that detainees held overseas were mistreated when they were involved in operations, but it was not always possible to "reduce the risk to zero".
The report said that ultimately it was for ministers to decide whether the needs of national security outweighed the concerns of possible mistreatment.
It follows a number of high profile court cases - most notably by former Guantanamo Bay detainee Binyam Mohamed - claiming MI5 officers had been complicit in their mistreatment at the hands of foreign agencies, including those of the US and Pakistan.
One MI5 officer is currently facing a criminal investigation by Scotland Yard.
The report said that while the UK had put in place measures to ensure detainees held in its custody were not subjected to torture or abuse, it could not always have the same level of assurance when they were held abroad.
"We cannot get all the intelligence we need from our own sources because the terrorist groups we face are scattered around the world and our resources are finite. So we must work with intelligence and security agencies overseas," it said.
"Some of them share our standards and laws while others do not. But we cannot afford the luxury of only dealing with those that do. The intelligence we get from others saves British lives."
It stressed that ministers took their responsibility to balance national security interests with human rights concerns "very seriously".
"If the risk of mistreatment is too high then we will not go ahead with an operation. This is not just a theoretical possibility - operations have been stopped because the risk of mistreatment was judged to be too high," it said.
"But this is never an easy judgment and we would be failing in our twin duties to defend the country and to uphold human rights if we pretended that there was never a tension between the two."