David Blunkett's ministerial attempt to change how suspects are tried in court came in for particular criticism on Thursday from one of Britain's most senior lawyers - a peer in the minister's own political party.
Baroness Helena Kennedy condemned changes that could allow secret trials, lower the burden of proof and bring pre-emptive charges so that "potential terrorists" can be put on trial before the crime takes place.
Speaking to BBC radio, Kennedy said: "It's as if David Blunkett takes his lessons in jurisprudence from Robert Mugabe, he really is a shameless authoritarian.
"I think we can be confident that many of his colleagues in the cabinet, including particularly the attorney general, will sit on this because it really is an affront to the rule of law."
Blunkett's proposals by far surpass any emergency powers taken at the height of the Irish Republican Army's bombing campaign against mainland Britain in the 1970s.
If the plans - announced during the Home Secretary's trip to India - are given the go ahead in parliament, security-vetted judges appointed by the government would try suspects behind closed doors.
There would be no jury and those in court would be banned from disclosing sensitive evidence. Defendants could also be found guilty on weaker evidence than at present.
"It's as if David Blunkett takes his lessons in jurisprudence from Robert Mugabe, he really is a shameless authoritarian"
Baroness Helena Kennedy,
Labour party peer
Currently jurors are told they must be sure "beyond reasonable doubt" that a defendant is guilty. Under the new proposals, government judges could convict on "the balance of probabilities".
Lawyer Louise Christian, who represents the family of Feroz Abbasi, a British citizen detained at the US base in Guantanamo Bay said such changes would be unprecedented. "It's an attack on the fundamentals of the criminal justice system."
But Home Office spokesman said Blunkett wanted tighter laws because bombers were not deterred from committing attacks by the threat of being jailed.
"We need to address that question through the criminal law in preventing terrorism rather than merely reacting after the event," the spokesman said.
Civil rights campaigners denounced the plans as unacceptable and said they would not make Britain any safer.
"Britain already has the most draconian anti-terror laws in Western Europe," said Mark Littlewood, campaigns director of civil rights group Liberty.
"To add to these by further undermining trial by jury and radically reducing the burden of proof is wholly unacceptable."
Britain currently holds 16 foreign detainees under anti-terror laws rushed in after the 2001 attacks on the United States to allow the indefinite detention of suspected international terrorists without charge.