Britain's moral standing in the world is at risk unless major changes are made to a controversial piece of legislation that will see a rise in secret court hearings, a joint report from a senior Tory and a human rights barrister has warned.
The Justice and Security Bill, which goes to committee stage in the House of Commons on Tuesday, outlines plans to allow court doors to close and evidence to be heard in secret on grounds of national security.
But in a scathing report for the Centre for Policy Studies think-tank, Conservative MP Andrew Tyrie and Anthony Peto QC said the bill would make it more difficult to establish the truth about Britain's complicity in kidnap and torture.
Urging the government to alter the legislation, the report said "ministers still have the scope to enhance, rather than diminish, Britain's moral standing".
It goes on: "That Britain allowed itself to be dragged into complicity in 'extraordinary rendition' - the kidnap and torture of individuals as a matter of policy - is a disgrace.
"That, nearly a decade later, the extent and limits of Britain's involvement are still unknown is almost as shocking.
"Far from bolstering that confidence, the Justice and Security Bill would weaken it. The effect of the Government's proposals would make it more difficult to establish the truth about Britain's complicity in kidnap and torture. The bill would provide a route neither more just nor more secure."
The report targets three major areas of concern in the bill.
Firstly, the expansion of secret justice through the introduction of Closed Material Procedures (CMPs) to civil cases.
Secondly, removing the courts' power to hear special applications, which seek the disclosure of information held by UK authorities, in cases deemed to be "sensitive".
And finally, inadequate proposals to strengthen the Intelligence and Security Committee, which is supposed to oversee the intelligence services but which failed to uncover the truth about rendition.
Tyrie and Peto found changes introduced by the House of Lords were not sufficient to make it "less unacceptable".
The report demands further amendments at committee stage, including ensuring a judge should have to exhaust all possibilities before considering the use of a secret hearing.
The bill was given a second reading by a majority of 244 after Cabinet minister Ken Clarke insisted the legislation was necessary to allow the security and intelligence agencies to defend themselves in court.
Clarke said the legislation would also allow the Government to fight claims when it is being sued rather than simply settle them out of court because giving evidence would have compromised intelligence sources.
Nick Pickles, director of civil liberties campaign group Big Brother Watch, backed the findings of Tyrie and Peto's report.
He said: "Open justice is an essential part of keeping the Government in check. There is a clear danger that the Justice and Security Bill would draw a cloak of secrecy over wrongdoing while doing little to improve the oversight of intelligence agencies.
"This legislation does not deal with issues of public safety but proposes sweeping restrictions on the ability of ordinary people to challenge assertions made by the state in court."
Ken Clarke said: "This Bill will allow light to be shone on material that is currently kept in the dark. It will allow for cases to be heard where there is currently no means of hearing them. It will allow judges to examine national security sensitive material and establish the truth which is just not possible at present.
"This should give the public greater confidence that the intelligence services are being held to account.
"It is simply not correct to say that the Bill will undermine the public's ability to know what has truly happened regarding British involvement in rendition. In practice nothing will be heard in closed court under these proposals which is currently heard in open. Crucially, the Bill will mean the public receives a final judgment in more cases as to whether the Government is culpable or not.
"The Bill will ensure that we get to the bottom of more of the sorts of cases we all want to see resolved. Retaining the status quo, or exhausting PII first, which ensures material which is national security sensitive is excluded from the hearing, is quite unequivocally not going to help us get to the bottom of questions about rendition."