David Cameron calls for support for new spying measures
David Cameron has pleaded for support for plans to ensure terrorists and child snatchers cannot have a "safe space" to communicate online beyond the reach of the authorities.
The Prime Minister insisted the UK's spies and police needed to be able to see who suspects had communicated with over the internet.
Proposed new laws will be published on Wednesday covering the tools available to police and intelligence agencies to fight terrorism and serious crime in the digital age.
In a potential area of controversy, measures requiring internet firms to store internet connection records (ICRs) to respond to the increasing use of apps and social media for communication are expected to be included in the draft Investigatory Powers Bill.
However, sources said access to ICRs will be controlled and they will not include a full browsing history or reveal every web page visited, with strict limits on accessing the records.
Security services will retain the capacity to intercept the content of communications after obtaining a warrant.
It is understood that ministers have ruled out any proposal to restrict encryption or ban it, despite fears in the intelligence community that advanced online security measures risk leaving them locked out of some areas of cyber space.
Mr Cameron told ITV's This Morning: " At heart what this whole Investigatory Powers Bill is really about is actually something quite simple, because we all know when it comes to missing children or hideous crimes and the like we all know it's absolutely vital for the police to be able to know who called who and when."
He said that communications data - in the form of telephone records - could be used to prove that under current laws governing the old technology.
"The point we are making in this Bill is, of course lots of people now communicate using email or websites in order to do exactly the same thing. So we need to know who called who and when.
"So communications data - not the content of the call, that's governed separately - but the 'who called who and when', we do need to make sure that we can follow that online as well as through a telephone call."
In a call for public and political support for the new measures he said: "As Prime Minister I would just say to people 'please, let's not have a situation where we give terrorists, criminals, child abductors, safe spaces to communicate'.
"It's not a safe space for them to communicate on a fixed line telephone or a mobile phone, we shouldn't allow the internet to be a safe space for them to communicate and do bad things.'"
In the new legislation ministers are also expected to propose a radical overhaul of the current oversight regime, including the appointment of a senior judge in a newly created role of Investigatory Powers Commissioner who will hold agencies and law enforcement to account.
It remains unclear w hether proposals for judges to take over from Secretaries of State in signing warrants for interception operations will be included, however.
Asked about the issue Mr Cameron said: "I think politicians do have a role. We will set out our plans on Wednesday, but politicians do have a role, not least to get this area of law right."
Whitehall sources have sought to distance the new legislation from the abandoned Communications Data Bill, which was labelled the "Snoopers' Charter" after it was drawn up in 2012, saying some of its "more contentious" tactics have been ruled out.