The Defence Secretary, Philip Hammond, has admitted up to 90 Afghans are being held without charge in the main British military base in Afghanistan.
Mr Hammond told ITV News that abuse taking place at one Afghan facility had left Britain "uncomfortable" with handing the men over, but that they could be handed over to the Afghan authorities within three weeks.
His comments came after lawyers acting on behalf of some of the suspected insurgents claimed their internment could have been unlawful.
British forces in Afghanistan, operating as part of the International Security Assistance Force (Isaf), are allowed to detain suspects for 96 hours but can hold them for longer in "exceptional circumstances", the Ministry of Defence said.
However, lawyers representing eight of the men said they had been held by the British Army for up to 14 months without charge, after they were arrested by soldiers in raids in villages in Helmand and Kandahar provinces.
Mr Hammond said he would now go to the court within the next few days to gain approval for the plans to transfer the detainees.
Earlier today, Phil Shiner of Public Interests Lawyers, whose firm has begun legal proceedings on behalf of two of the men, said:
What happens is the UK could have trained the Afghan authorities to detain people lawfully with proper standards and making sure that they are treated humanely.
They could have then monitored that, including with ad hoc inspections to make sure that the Afghans were obeying the law. They have chosen not to do so.
And they have chosen to go down a route which I think is completely worrying and entirely unconstitutional where no one's been told, Parliament has not been told that we have this secret facility.
Whatever the solution is, flagrant breaches of the common law and international law, that's not the answer.
And Afghanistan's ambassador to the UK Mohammad Daud Yaar said the Government should hand over the detainees, saying investigators had found "some occasions of torture" in Afghan prisons but it was "not systematic".