A legal charity is to sue the UK government to force it to reveal the identities of two men being held in secret at a US base in Afghanistan.

Reprieve said the men were arrested by British troops in Iraq in 2004, handed to the US and "illegally rendered" to Bagram Air Force Base.

It says the men are among hundreds held "beyond the rule of law".

It had previously told Reprieve, which is seeking to represent the men, that it would violate their rights under the Data Protection Act to reveal the identities.

The charity says that since 2004 the men have been held beyond the rule of law, far from their families, and have never been charged with an offence.

It says a review of their status by the US military was characterised by a US federal judge as falling "well short of what the Supreme Court found inadequate at Guantanamo".

Reprieve's director Clive Stafford Smith said: "These two men have been held in appalling conditions for five years, and for all that time the British government chose to do nothing.