More people could lose their lives if the government's new communications data bill is not passed, the home secretary has warned.
The legislation, dubbed a 'snooper's charter' by campaigners opposed to its implementation, would force internet providers and telecoms companies to keep details of all communications made by the public accessible to the police for a year.
Opponents to the measure argue that allowing so much access to private information is an infringement of people's civil liberties.
But Theresa May raised the stakes in an interview with the Sun today, saying lives could be lost if the bill is not passed.
"The people who say they're against this bill need to look victims of serious crime, terrorism and child sex offences in the eye and tell them why they're not prepared to give the police the powers they need to protect the public," she said.
"Anybody who is against this bill is putting politics before people's lives. We would certainly see criminals going free as a result of this."
Only information relating to who and where the message was sent to and from would be made available to police. The contents of emails, text messages and other forms of communication would remain protected.
May argues it is not just terrorists who would be affected by the new laws, however.
"There will be paedophiles who will not be identified and it will reduce our ability to deal with this serious organised crime," she added.
Liberal Democrat support for the bill may be waning as MPs await the findings of the Commons' intelligence and security committee, due to report tomorrow.
Liberal Democrat home affairs spokesman Julian Huppert said in September: "The major problem was with the clause which gives the home secretary virtually unbridled power to snoop on someone's internet activity".
Business secretary Vince Cable has also gone on record as having reservations about the proposals, arguing that it could prove costly for business.
The plans were first proposed by Labour in 2009.