Ian MacDonald QC condemned the indefinite detention of suspects without trial or the right to know the evidence against them as “an odious blot on our legal landscape”.

MacDonald and 14 other special advocates are virtually the only legal representation the 12 foreign suspects currently held under anti-terror legislation can access. If other advocates follow his lead, it would leave the government in difficulties over operating the secret courts.

The defendants’ cases are heard in a basement by the Special Immigration Appeals Commission, which sometimes requires defendants leave court when evidence against them is heard. Only spies, government ministers and the security-cleared special advocates are allowed to see all evidence.

MacDonald, who has impeccable credentials as a radical Labour lawyer now specialising in immigration, has been in high-profile cases including the the Balcombe Street Siege and the Stephen Lawrence inquiry. He said that though he disapproved of the commission procedures, he became involved because he thought he could make a difference.

Last February he wrote an open letter condemning the system, saying: “It would contradict three of the cardinal principles of criminal justice: public trial by an impartial judge and jury of one’s peers, proof of guilt beyond reasonable doubt, and a right to know, comment on and respond to the case made against the accused.”

Explore UK News

• Crime News

• Education News

• Health News

• Science News

• Scotland News

Times Recommends

• I was not the underdog, says Frost
• First-timer scoops Booker with Indian tale
• Churchill 'bribed Franco's generals'