Shaker Aamer, the last British resident held at Guantanamo Bay, is to be released, a British Government spokesman said.
The US government has notified the UK authorities that it now intends to return Mr Aamer to Britain.
"The Government has regularly raised Mr Aamer's case with the US authorities and we support President (Barack) Obama's commitment to closing the detention facility at Guantanamo Bay," the spokesman said.
"In terms of next steps, we understand that the US Government has notified Congress of this decision and once that notice period has been concluded, Mr Aamer will be returned to the UK."