Nick Clegg will position himself in stark opposition to David Cameron and to Boris Johnson over mooted attempts to revive the so-called 'snooper's charter'.
Clegg will condemn the prime minister for promising to protect free speech in the wake of the Charlie Hebdo massacre while planning new laws that erode British freedoms.
Tory plans to revive the so-called snoopers' charter to make it easier for intelligence services to track email and web traffic are "not proportionate" or "harmless", the Deputy Prime Minister will insist.
London Mayor Johnson has been one of the most prominent voices, since the attack on the satirical newspaper by Islamist gunman, to call for new powers of surveillance.
Boris Johnson on greater surveillance powers: 'There's a small but significant number of people we have to monitor.' pic.twitter.com/JsN43bmRxB— BBC Radio 4 Today (@BBCr4today) January 13, 2015
Earlier Johnson had said he was "not particularly interested in this civil liberties stuff when it comes to these people's emails and mobile phone conversations".
Civil liberties campaigners have warned against any attempt to use the Charlie Hebdo massacre to extend surveillance powers.
Big Brother Watch director Emma Carr said: "It is wholly unacceptable for this tragedy in Paris to be used as a means to call for a return of the snooper's charter. It is the wrong solution and would divert resources from focused surveillance operations at a time when the agencies are already struggling to cope with the volume of information available."
The row came as reports from France suggested that as many as six members of the terror cell behind the deadly attacks in Paris may still be at large.
The Obama administration also apologised last night for not sending a senior government figure to Sunday's million-person march alongside dozens of world leaders.
In an apparent swipe at the Prime Minister, who pledged to introduce "more comprehensive" powers to monitor terror suspects yesterday, Clegg will claim measures are sometimes introduced "in the name of public safety that undermine the very freedoms we cherish".
"The irony appears to be lost on some politicians who say in one breath that they will defend freedom of expression and then in the next advocate a huge encroachment on the freedom of all British citizens," he will say in a speech to journalists at the Irish Embassy.
"Let me be really clear, we have every right to invade the privacy of terrorists and those we think want to do us harm - but we should not equate that with invading the privacy of every single person in the UK. They are not the same thing.
"The snoopers' charter is not targeted. It's not proportionate. It's not harmless.
"It would be a new and dramatic shift in the relationship between the state and the individual."
Plans for a communications data Bill - nicknamed the "snoopers' charter" by critics - were blocked by Lib Dems but Conservatives want to revive the legislation if they secure an overall majority in May's general election.
The legislation, which was tabled in draft form by Home Secretary Theresa May in 2012, would have extended the requirement for companies to retain phone and email data to include records - but not the content - of every individual's internet browsing activity, including use of social media sites like Facebook, internet gaming, and mobile phone messaging services.
Cameron yesterday said that he wanted to ensure there is no "safe space" for terrorists to communicate over the internet, in the wake of the Paris terror attacks.
He said that as well as well as the snoopers' charter, new legislation will be required to enable the agencies to continue to intercept phone calls and access the content of electronic communications - on the basis of a warrant signed by the home secretary - when existing powers expire in 2016.
Clegg will argue "we do not make ourselves safer by making ourselves less free".
The Lib Dem leader will also underline his party's proposals for a Bill of Rights that would enshrine the right to free expression.
"If we really believe freedom of speech is a founding principle of our democracy, then we must act to protect it," he will say.
"I look enviously at America, where every schoolchild is taught from day one that they have inalienable rights - including free expression - which are a fundamental part of what it means to be American.
"I want us to have the same. The time has come for a written constitution with a Bill of Rights. The Liberal Democrats are committed to a constitutional convention after the general election, and deciding how we enshrine free speech in a British Bill of Rights should be at the heart of it.
"We must always defend the British values of freedom, openness and tolerance. We must always defend the rights of individuals to express themselves freely. And we must always defend the right of a free press to do its work without fear or favour," he will add.
"It is at times like these, when our freedoms are under threat, that we must stand up for them most of all."Suggest a correction