Human rights groups have furiously condemned "kafkaesque" plans by cabinet minister Ken Clarke over secret court legislation, as the government prepared for what is expected to be a bruising battle in the House of Lords over the bill.
Detailed scrutiny begins on Monday of the Justice and Security Bill, which controversially allows more civil cases to be held in secret without claimants being able to hear the evidence against them.
Amnesty International’s UK researcher Alice Wyss said in a statement as the Lords prepared to consider the bill: “We’ve said repeatedly that the Justice and Security Bill is a real threat to the principles of fairness and open justice in the UK.
“Under the bill we’re likely to end up with evidence that is kept secret and lawyers that can’t talk to those they represent - it’s a secret justice system straight from the pages of a Kafka novel.
“A person who can credibly accuse the UK of responsibility over their torture, enforced disappearance or other human rights violation has a right to a fair and effective remedy.
"The public also has a right to know the truth about whether and how the government has been involved.
“The bill seems designed to allow the government to throw a cloak of secrecy over wrongdoing. We want the House of Lords to reject secret justice and stand up for the principle that justice needs to be done and seen to be done.”
Former director of public prosecutions Ken Macdonald, a Liberal Democrat peer, said he expected the House of Lords to force significant changes limiting its scope and giving more discretion to judges.
Clarke said the change was needed to prevent the UK becoming a "global magnet" for people seeking taxpayer-funded settlements because they knew sensitive security-based evidence could not be against them in court.
Some 16 terror suspects, including former Guantanamo Bay detainee Binyam Mohamed, received a multimillion-pound payout last November after they claimed they were mistreated by US and British security and intelligence officials.
Former MI5 chief Baroness Manningham-Buller said the ability to share intelligence would be "seriously jeopardised" - putting the UK in danger - unless judges are allowed to hear evidence in secret.
But Amnesty said the moves could potentially mean that lawyers who are seeking to prosecute UK officials for serious wrongdoing, such as torture and enforced disappearance, will be prevented from seeing crucial documents on “national security” grounds.
The charity said this could mean secrecy could be maintained indefinitely, even if there is an overwhelming public interest in disclosure.
The cross-party joint committee on human rights, which investigated the proposals, reported last week that ministers had "failed to prove a pressing need" for the new powers
"Parliament should only accept such a departure when the necessity for it has been properly and persuasively justified," the cross-party panel said - calling for the scope of the legislation to be drastically narrowed.
Liberal Democrat peers are under pressure from activists to oppose the legislation after the party's annual conference voted overwhelmingly for them to press for its "withdrawal or defeat".
They will meet at lunchtime to discuss whipping arrangements, a party spokesman said.
A number of prominent Tory MPs, including former shadow home secretary David Davis, are also hostile.
Lord Macdonald told BBC Radio 4's Westminster Hour: "I don't think the Lords is going to pass this bill as it's presently constituted. It seems to me the basic premise of this Bill, which is closed justice, is a premise which Liberals can only accept with very great reluctance and only in the most exceptional circumstances.
"We want a bill that delivers that."
The discretion of judges was "extremely fettered" under the present proposals, he said, and the legislation was "far too broad" and could end with secret courts being used in wide range of cases.
"I think many peers are going to conclude that if there has to be a closed material procedure we have to have it much more strictly curtailed and the judge has to have the final discretion balancing the interests of justice with national security and the interests of fairness.
"I think those amendments will carry in the House of Lords."
Clarke, who retained responsibility for the legislation despite losing his justice secretary post in the reshuffle, said:
"Under the current system the finest, wisest judges in the world are barred from taking into account the evidence which lies at the heart of some of the most important civil court cases that go before them.
"Sensible citizens are denied a judgment on allegations which question the very nature of our democracy. Taxpayers are put in the position of funding settlements to former detainees who have not been able to prove their case.
"And the increasing number of cases suggests that this unchallenged availability of damages threatens to make the United Kingdom a global magnet for this sort of litigation.
"We civil libertarians must ensure we step away from the comforts of legal purism, and ground our approach to this Bill in the realities of the problems we face. If we do not we will miss a golden opportunity to improve the accountability of our security and intelligence agencies, and to shore up our reputation as a reliable international partner."
Legal action charity Reprieve released a statement saying Clarke's repeated flip-flopping on amendments to the Bill has shown he could not be trusted not to also introduce "secret inquests".
The charity repeatedly asked for assurances that inquests, where national security is a factor, would not be held in secret, which Clarke promised to amend. But the charity noticed "the discovery of a little-noticed clause in the Bill which would have allowed them to be reinstated, [and] Clarke was forced to again announce that the legislation had been amended to remove this possibility altogether.
Reprieve's Executive Director, Clare Algar said: “Ken Clarke has now announced the same ‘concession’ an incredible three times.
"On each of those occasions, the minister assured us that secret inquests had gone for good – yet twice he has been forced to admit that this wasn’t the case.
"This must surely call into question the Government’s sincerity when it claims that the legislation has significantly changed. How can we now believe anything Ken Clarke tells us about the dangerous Secret Courts Bill?”