British MPs Urge US to Free Last UK Resident Held in Guantanamo

British lawmakers called on the US government on Tuesday to release the last British resident being held at Guantanamo Bay, describing his treatment as "inhuman".

Shaker Aamer, a Saudi married to a Briton with children living in London, has been held at Guantanamo for 13 years despite his lawyers saying he was cleared by US authorities for release in 2007, and has not been charged with any crime.

Prime Minister David Cameron lobbied US President Barack Obama for Aamer's release during a visit to Washington in January and was told a review of his case would be prioritised.

"The case of Shaker Aamer is one of the worst cases of a miscarriage of justice in the last three decades at least ... He has endured harsh, and brutal and inhuman treatment," opposition Labour lawmaker John McDonnell told a debate in parliament that saw members of all major political parties criticise Aamer's treatment and call for his release.

"Now is the time for action not words ... his health has deteriorated significantly."

Obama has pledged to close the detention centre in Cuba, opened in 2002 to house suspected militants, but faces obstacles from Congress including some right-wing Republican senators calling for a moratorium on the release of remaining detainees.

McDonnell said a delegation of lawmakers planned to head to Washington shortly to meet with US officials about the case.

Tobias Ellwood, a junior minister in Britain's Foreign Office, said the government was committed to bringing Aamer back to Britain and wanted him released "as a matter of urgency".

According to rights group Amnesty International, Aamer moved to Britain in 1996 and was in Afghanistan doing voluntary work for an Islamic charity when he was captured by Afghan Northern Alliance forces in 2001 and handed to the U.S. military.

All British nationals and citizens have been released from Guantanamo.

Some lawmakers expressed concern Aamer was still being held because he "had seen too much" and would be a threat to America if released, but senior Liberal Democrat Tim Farron, said keeping Guantanamo open presented a greater danger.

The camp is a motivation for fighters joining Islamic State insurgents, he said, driving a sense that the West was acting in a way that "deserved a response", he said.

"It is not in America's interests to continue to pour petrol on that fire. The incarceration of Shaker Aamer ... is unjust, it is wicked and it is fundamentally counter to America's interests."