Concerns over secret courts
18 November 2012 Last updated at 20:43 GMT
It's a bill which " undermines the fundamentals of both liberty and democracy" says the former Shadow Home Secretary David Davis.
He's referring to the Justice and Security Bill, which is in the Lords this week.
One of its provisions is to allow secret trials in civil cases where sensitive security-related material is involved.
Supporters of the Bill, like the former head of MI5 , Baroness Manningham-Buller, argue that, at the moment, information gained from secret intelligence can't be used in an open court becuase it might jeopardise theis country's security or the lives of the agents who provided it.
She says the government currently has to settle cases out of court when, for example it's been accused of complicity in torture in another country, and can't defend itself in court because that would mean releasing sensitive intelligence material.
This Bill would remedy that.
Government parties, including the Liberal Democrats, will be whipped to support it but some remain nervous, including the former Director of Public Prosecutions, the Lib Dem peer Lord Macdonald.
He told Carolyn why.