Campaigners against a new generation of secret courts are confident they will be able to introduce fundamental changes to the controversial measure next week by launching parliamentary guerrilla tactics dubbed "ping pong with grenades".
Amid warnings that the government is planning to introduce Russian-style secret courts, the government is being warned that peers are prepared to exhaust a series of parliamentary devices when the bill sanctioning the changes reaches its final stage on Tuesday.
Peers are planning to table amendments to the justice and security bill that would ensure judges are given complete discretion over the new system and the courts are used as a last resort. This will be done when the bill reaches "ping pong" stage, in which it shuttles between the two houses of parliament as MPs and peers haggle over last-minute amendments.
The upper house usually avoids a prolonged fight with the Commons. But campaigners, who point out that the changes were not included in the coalition agreement, say peers are digging in for a long fight because the Commons cannot use its usual powers to force through a bill by invoking the Parliament Act. The Commons cannot do this with the justice and security bill because it originated in the upper house.
Campaigners believe they have another weapon. They say that if no agreement is reached between the Lords and the Commons by the beginning of May, when parliament is prorogued before the Queen's speech on 8 May, it may die. This is because it may be too late to designate the bill as a "carry over" measure that should be allowed to continue into the next parliamentary session. The government would have to table a "carry over" amendment in the Lords, which it would struggle to win.
One campaigner said: "The government have been caught napping on this. Next week we will see real ping pong with grenades."
Andrew Tyrie, the Conservative MP for Chichester who has been one of the leading voices against the bill, told the Guardian: "We need to think of this as a massive experiment with the way justice has historically been done in Britain. The principle that you should be able to find out what the other side are saying about your plea is so deeply entrenched in British and Anglo-Saxon justice it is amazing it is going more or less on the nod.
"You have only got to think about all those countries that do have secret courts to see why we don't really want to join their club. There are about 130 run by dictators – Russia has secret courts."
The government plans to extend secret courts, known as closed material procedures, into the main civil courts in England and Wales. The bill would limit access to some sensitive intelligence to the judge and to special advocates cleared for security who would represent claimants.
The government introduced the bill after the public airing of evidence during litigation brought on behalf of Binyam Mohamed and other former Guantánamo Bay detainees. The court of appeal agreed to disclose CIA information which showed MI5 and MI6 knew that Mohamed, a UK resident, had been abused.
The Lords amendments are designed to:
Guarantee full judicial discretion to ensure the new courts are only used as a last resort after all other avenues have been exhausted. The government is opposed to this because they want to avoid public immunity interest, which would give judges discretion to make some of the material public.
Introduce a renewal clause to ensure the bill would have to be reviewed and approved in every parliament.
The government has succeeded in overturning previous Lords amendments by whipping coalition MPs to overturn them. Tyrie and the Lib Dem president, Tim Farron, have rebelled against the government on the bill.
Tyrie said: "Everything hinges on the Lords sticking to their position. The judges should decide, not ministers. The government heavily qualified the judicial discretion which, rightly, the Lords put on the face of the bill. I very much hope the Lords back the spirit of their original amendments.
"This bill started in the Lords so they have a disproportionate say. This is a very important bill. It is ultimately about the type of country we want to live in.
"This bill has been introduced partly because parts of the executive didn't like the exposure given to Britain's complicity in rendition. We should be getting to the bottom of this – Britain's complicity in kidnap and torture – not closing down routes to exposing it."
Tyrie said the government's arguments were weak. Ministers have said the courts are necessary to avoid large compensation payments which are being made at the moment because some sensitive intelligence material cannot be heard in open court and is therefore excluded.
Sadiq Khan, the shadow justice secretary, said: "The decision on whether or not to have court hearings in secret should be decided by a judge, not a minister. We will be pushing to ensure all options that would maintain court hearings in the open are considered before a hearing becomes secret and also that a proper test is applied by a judge before opting for closed material proceedings.
"We also want the bill to have to be renewed once by each parliament. We all want to see justice done in these very difficult cases, but without our changes being accepted this is unlikely to happen."
Nick Clegg suffered a defeat at the recent Liberal Democrat spring conference when the party voted to reject the bill. Jo Shaw, a veteran Lib Dem who resigned from the party after moving the motion, confronted him on his LBC 97.3 radio phone-in on Thursday.
Shaw said: "Hello there. Nick, why are [you] whipping Lib Dem peers to support the justice and security bill next week when there is no evidence it is needed, it provides a toolkit for cover-ups of torture and kidnap and the entire Liberal Democrat party is united against it?"
Clegg defended the changes on the grounds that the special courts would be convened in "exceptional cases" to avoid the current situation in which large compensation payments were being made because some intelligence could not be heard in open court.
