David Blunkett was last night accused of jeopardising any future trial of a terror suspect arrested after a massive security operation that may have foiled an al-Qa'ida suicide attack in this country.
Scotland Yard detectives are still questioning Islamic student Sajit Badat and analysing explosives allegedly found at his parents' home in Gloucester.
Within hours of the arrest on Thursday morning the Home Secretary appeared on national television to describe the 24-year-old as being "part of a wider network", claiming he posed a "very real threat to the life and liberty of our country".
His comments provoked protests from politicians and civil rights lawyers who accused the Home Secretary of acting as judge and jury in any forthcoming trial. They said he also risked sabotaging an ongoing anti-terrorist surveillance investigation at a time when Britain is at its highest state of emergency since the 11 September attacks.
Mr Badat was being questioned yesterday at a high-security police station in London about suspected links with the convicted "shoe bomber" Richard Reid. The al-Qa'ida terrorist was sentenced to life imprisonment in America after he attempted to blow up an American Airlines flight in December 2001.
Yesterday the Attorney General, Lord Goldsmith QC, added to the Home Secretary's embarrassment when he issued a warning to the media reminding of the dangers of pre-trial publicity in high-profile cases.
Dominic Grieve MP, the shadow Attorney General, said he was "astonished" when he heard the Home Secretary's remarks. "He is doing exactly the sort of thing that he has condemned the press for doing - making comments that are prejudicial to any future trial," he said.
The developments came as police in Germany and Italy arrested four al-Qa'ida suspects accused of attempting to recruit suicide bombers.