Police are to get powers to force internet firms to hand over details that could help identify suspected terrorists and paedophiles, prompting another row between the Lib Dems and Tories about "snooping" on the British public.
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 it would boost national security but again complained that Liberal Democrats were blocking further steps, including the return of the so-called "Snooper's Charter" law.
The Snooper's Charter has long divided the Lib Dems and the Tories
The law, currently languishing in parliament, would require ISPs to record people's internet activity, including social media use, online browsing and online gaming, for 12 months.
"Loss of the capabilities on which we have always relied is the great danger we face," Mrs May said. "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."
However, the Lib Dems insisted that legislation was "dead and buried".
The party also stressed that Nick Clegg had been calling for the IP measures since spring 2013.
"It is good news that the Home Office has finally got round to producing proposals on this after being repeatedly asked by Nick Clegg. These can now be agreed and acted on in the upcoming Bill," a Lib Dem spokesman said.
"This is exactly the kind of thing that we need to take action on, rather than proposing an unnecessary, unworkable and disproportionate Snooper's Charter. There is absolutely no chance of that illiberal Bill coming back under the coalition Government - it's dead and buried.
"The issue of IP address matching only resurfaced as a result of deeply misleading claims made in Theresa May's conference speech. That is what has prompted the Home Office to stop sitting on their hands."
An aide to Clegg told the Daily Mail that Mrs May's claims that the Lib Dems' stance had "put children's lives at risk" as "deeply misleading".
Emma Carr, director of campaign group Big Brother Watch, said: "Before setting her sights on reviving the snooper's charter, the Home Secretary should address the fact that one of the biggest challenges facing the police is making use of the huge volume of data that is already available, including data from social media and internet companies.
"The snooper's charter would not have addressed this, while diverting billions from investing in skills and training for the police."