Police will be able to force internet firms to hand over details that could help identify suspected terrorists and paedophiles under new laws set to be introduced by Theresa May.
The Anti-Terrorism and Security Bill will oblige internet service providers (ISPs) to retain information linking Internet Protocol (IP) addresses to individual users.
Home Secretary Theresa May said the measure would boost national security - but again complained that Liberal Democrats were blocking further steps.
"Loss of the capabilities on which we have always relied is the great danger we face," Mrs May said.
The Bill provides the opportunity to resolve the very real problems that exist around IP resolution and is a step in the right direction towards bridging the overall communications data capability gap.
But I believe we need to make further changes to the law. It is a matter of national security and we must keep on making the case for the Communications Data Bill until we get the changes we need.
- Theresa May
However, the Lib Dems insisted that legislation - branded the "Snooper's Charter" - was "dead and buried".
The party also stressed that Deputy Prime Minister Nick Clegg had been calling for the IP measures since spring 2013.