The High Court was urged today to order full disclosure of correspondence from America setting out the Obama administration's current stance on whether US intelligence outlining its agents' treatment of former terror detainee Binyam Mohamed should be made public.
Lawyers for Foreign Secretary David Miliband argued that the full text of letters between the US and UK governments must be protected by "public interest immunity".
But Ben Jaffey, for Mr Mohamed, said the public interest in disclosure – even if confined to lawyers involved in the case – was not outweighed by any coherent reason presented by the Foreign and Commonwealth Office.
He accused the FCO of using a "salami slicer" to release the correspondence bit by bit even though the US had agreed to disclose a fuller version than the two paragraphs handed over initially by Whitehall lawyers.
Lord Justice Thomas and Mr Justice Lloyd Jones reserved judgment on the issue, which is part of an on-going legal row over the judges' desire to make public a brief summary of US intelligence on Mr Mohamed's treatment.
A month ago, the judges agreed to reopen their original judgment on the first stage of Mr Mohamed's case, in which he alleges he was tortured at the hands of US and Pakistani intelligence services with the collusion of British agents, with a view to inserting a summary of the US data.
The FCO then announced that the Obama administration remained opposed to disclosure of the information by a British court.
The US had stressed that that disclosure could result in "serious damage to UK and US national security".
Mr Mohamed, 30, an Ethiopian, was granted refugee status in Britain in 1994. He was detained in Pakistan in 2002 on suspicion of involvement in terrorism and "rendered" to Morocco and Afghanistan. After being subjected to alleged torture, he was sent to Guantanamo Bay in 2004. Charges were dropped last year and he returned to the UK. Last month a US court said Mr Mohamed could sue a subsidiary of the aviation company Boeing for complicity in the rendition. Lawyers for Mr Mohamed began legal action against Jeppesen in 2007 for its alleged role in the illegal transfer of prisoners between secret detention centres. The company is said to have supplied logistical support.
A final decision on whether to publish the intelligence details is expected after a further hearing in June.