Nick Clegg has come under renewed pressure over his decision to block the so-called "snooper's charter”.
The Deputy Prime Minister blocked the new laws giving police and security services powers to monitor internet and email activity earlier this month, but demands for the legislation to be introduced have heightened in the wake of the murder of Drummer Lee Rigby in Woolwich last week.
Among the fiercest critics was one of Clegg's own peers, who accused the Lib Dem leader of bringing the Communications Data Bill to a halt for "purely political" reasons.
Lord Carlile suggested the reforms it contains might have prevented the soldier's death if they had been introduced two years ago and were "very likely" to stop future attacks.
Home Secretary Theresa May indicated on Sunday that the plans would be revived and appeared to be gearing up for a fight with Liberal Democrats.
Former Conservative leader Michael Howard suggested the party should join forces with Labour to get new laws passed if Liberal Democrats continue to prevent reform – a move that Labour's Ed Miliband has previously indicated he is open to.
"If the Liberal Democrats maintain their opposition to it, I think there's a case for the Conservative Party passing that legislation with support from the Labour Party," Lord Howard told BBC Radio 5 live.
"The prime minister's got to act in the national interest to give the protection to people of this country that they need and deserve from horrible attacks of this kind, and I think the Communications Data Bill could be an important element in that programme."
Labour former Home Secretary Alan Johnson said today he was "absolutely passionately" a supporter of reforms and suggested it was a resigning issue for May if she could not get the changes into law by 2015.
Asked whether she would quit over the matter, May told the BBC's Andrew Marr Show: "I have made my view very clear. We are now working through across the government what action we can take but I'm clear, the law enforcement agencies, the intelligence agencies need access to communications data and that is essential to them doing their job."
The Home Secretary said there was a reference to the plans in the Queen's Speech, adding: "I have always been clear that access to communications data is essential for law enforcement agencies and the intelligence agencies. There is a reducing capability in relation to access to communications data."
Lord Carlile, who until 2011 was the independent reviewer of government anti-terror laws, said in an article for the Mail on Sunday that just days before Drummer Rigby was killed he had written to Clegg warning "I fear that this may come to haunt you and the party if any terrorism event occurs which could otherwise have been avoided".
Speaking later to Murnaghan on Sky News he said: "We don't know whether if that bill had been enacted two years ago it would have prevented this incident.
"What we can certainly say is that it might have done and what we can absolutely say for certain is that if the communications data bill, with the safeguards that were agreed in the last session of parliament, was introduced then it would be very likely to prevent some attacks of this kind in the future."
He added: "The reason it was vetoed, as Nick Clegg the leader of my party knows very well, was purely political because of demands from inside the Liberal Democrats."
Lib Dem deputy leader Simon Hughes said there is "no evidence at all" that the communications bill could have prevent the Woolwich atrocity.
He told the programme: "The evidence base isn't as clear as I think he would argue it is."
A spokesman for the Deputy Prime Minister warned against "leaping to conclusions".
He added: "Both the Prime Minister and Deputy Prime Minister have cautioned against knee-jerk responses. There is currently no suggestion that the proposals in the draft communications data bill would have had any relevance to the sickening events.
"There are already substantial powers in place to track the communications of criminals and terrorists. As stated in the Queen's Speech, the Government will continue to work to address some of the challenges posed by new technology."
Emma Carr, deputy director of civil liberties campaign group Big Brother Watch, said: "It is remarkable for politicians to be jumping to legislation to monitor the entire country when all the evidence to date shows this horrific attack would not have been prevented by the communications data bill."
"Perhaps Lord Carlile should be explaining why he barely mentioned the issue of communications data in his formal reports to Parliament rather than resorting to ill-judged scaremongering," she added.
Liberty director Shami Chakrabarti said: "We urge the Home Secretary to ignore those who so shamelessly play politics with murder and fear. At times of tragedy, the last things to recycle are those familiar faces and discredited ideas that leave us no safer and less free. The terrorists can't shut down our open society. Why would we do it for them?"
Former Metropolitan Police chief Lord Blair said the Government would have to look again at laws to make internet providers store internet traffic.
He told Pienaar's Politics on BBC Radio 5live: "I just think they (opponents) are either misunderstanding or misrepresenting the argument because this isn't about the police listening to the telephone calls or watching what the person does in relation to a particular extremist site, it's actually just after an incident has happened or when there is a build up to an incident it's actually being able to say we need to know which phone this phone has been talking to? What sites has this person been examining?
"If you think of the scale of telephone traffic or internet use in the United Kingdom there is no possibility of people sitting in a darkened room examining everything. This is almost certainly a post facto event."
He added: "They certainly need to be a bit more real. I don't think they necessarily need to be less liberal. Because if I was suggesting that in some Stazi sense that every telephone call, every email, every internet was going to be monitored then you would have every right to say this is madness.
“What I am actually saying is in the event of a serious criminal or terrorist investigation, or immediately in the aftermath of a terrorist atrocity we are going to bitterly regret that we don't have this ability."