Home Secretary Theresa May is expected to unveil plans to claw back permanently almost 100 criminal justice measures from the European Union while retaining the controversial European arrest warrant.
In a compromise agreement with Liberal Democrats, it is reported she will tell MPs the UK will continue to support 35 EU powers - including Europol, the EU intelligence-sharing agency which co-ordinates police investigations across the bloc.
In a move to reassure Tory MPs who wanted her to go further in repatriating power from Brussels, The Guardian reported that she will say she intends to work with like-minded member states to reform the European arrest warrant.
The agreement - hammered out between Tory policy chief Oliver Letwin and the Lib Dem Treasury Chief Secretary Danny Alexander - followed months of wrangling between the coalition partners.
The Conservatives were reported to want to retain just 29 EU measures while the Lib Dems were said to be pushing for around 45.
The Guardian quoted a Lib Dem source as saying: "This is a deal; it is a compromise. It is good for the Liberal Democrats; it is good for the Conservatives. But most importantly it is good for the fight against crime."
Many Tory MPs have expressed concern over the European arrest warrant, arguing that it is used to extradite British nationals for relatively trivial offences who can then be held for lengthy periods while they await trial.
Mrs May is reported to be seeking agreement on a proportionality test which would limit its use to more serious offences.
Under the terms of the Lisbon Treaty, the UK has to opt out of all 133 measures under the justice and home affairs heading simultaneously. It can then seek to opt back in to those measures it wishes to retain.
Labour has warned that opting back in is likely to be a "very uncertain process", pointing to comments by EU Justice Commissioner Viviane Reding who said it would be "complex, time-consuming (and) leave a lot of legal uncertainty".