A former SAS soldier was served with a high court order yesterday preventing him from making fresh disclosures about how hundreds of Iraqis and Afghans captured by British and American special forces were rendered to prisons where they faced torture.

Ben Griffin could be jailed if he makes further disclosures about how people seized by special forces were allegedly mistreated and ended up in secret prisons in breach of the Geneva conventions and international law. Griffin, 29, left the British army in 2005 after three months in Baghdad, saying he disagreed with the "illegal" tactics of US troops.

He told a press conference hosted by the Stop the War Coalition this week that individuals detained by SAS troops in a joint UK-US special forces taskforce had ended up in interrogation centres in Iraq and Afghanistan, as well as Guantánamo Bay. He had not witnessed torture himself but added: "I have no doubt in my mind that non-combatants I personally detained were handed over to the Americans and subsequently tortured."

Referring to the government's admission that two US rendition flights containing terror suspects had landed at the British territory of Diego Garcia, Griffin said the use of British territory and airspace "pales into insignificance in light of the fact that it has been British soldiers detaining the victims of extraordinary rendition in the first place".

The Ministry of Defence said it did not comment on special forces' activities.

In a separate move, the media have been prevented by a court order from reporting a court martial of six SAS soldiers charged with a conspiracy to "defraud of a value of about £3,000".