The Deputy Prime Minister Nick Clegg has warned that Britain could become a "safe haven" for foreign criminals if it pulls out of the European Arrest Warrant.
The Conservative Home Secretary Theresa May plans to opt out of 133 EU-wide justice and policing measures, including the EAW.
After meeting campaigners, Mr Clegg said:
While some measures of European co-operation on crime are old, out of date or defunct, the police and other law enforcement agencies consistently tell us that other measures are essential for our national security and public safety.
The European Arrest Warrant is one of those key measures...as the police say, without it Britain could become a safe haven for Europe's criminals.
We want to improve the way the arrest warrant works.
But this key crime fighting tool should be reformed, not abandoned.
One of Mr Clegg's aides went further, telling the Financial Times:
It is incredible that people would risk the security and safety of British citizens for some anti-European posturing.
More top news
The five-piece dance group do not sing but their choreographed back-flips had the crowd cheering at their audition in tonight's episode.
Business Secretary Vince Cable says the party plans to double the number of employers offering apprenticeships to young people.
A study suggests people who are obese fall into six types including heavy drinking males, young healthy females and those in poorest health.