Cameron pledge over terror threats
David Cameron has vowed that a new Conservative government would introduce "comprehensive" legislation to ensure there is no "safe space" for terrorists to communicate over the internet.
In the wake of the Paris terror attacks, the Prime Minister said that the security and intelligence agencies needed "robust powers" in order to protect the public from violent extremists.
Mr Cameron has already indicated he would seek to revive measures in the abandoned draft communications data bill - dubbed the "snoopers' charter" by critics - enabling the agencies to track emails and other online communications.
At the same time, 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 expires in 2016.
Speaking at an event in Nottingham, Mr Cameron said that he wanted to act in a comprehensive fashion and that the powers he was seeking were "absolutely right" for a liberal democracy.
"The attacks in Paris once again demonstrated the scale of the terrorist threat that we face and the need to have robust powers through our intelligence and security agencies and policing in order to keep our people safe," he said.
"The powers that I believe we need, whether on communications data or on the content of communications, I am very comfortable that those are absolutely right for a modern, liberal democracy."
"The next government will have to legislate again in 2016. If I am prime minister, I will make sure that it is a comprehensive piece of legislation that makes sure we do not allow terrorists safe space to communicate with each other.
"That is the key principle: do we allow safe spaces for them to talk to each other? I say no, we don't, and we should legislate accordingly."
However the Liberal Democrats, who blocked the communications data bill, warned they would oppose any attempt to revive the measure which would have required internet service providers to store records of user's online activity (although not the content) - including emails, voice calls, and mobile phone messaging services as well as visits to social media - for 12 months.
Lib Dem Justice Minister Simon Hughes told BBC Radio 4's The World at One: "We have said 'no' and will say 'no' to blanket powers - because of the abuse of liberty by the few - to take away the liberties of the many.
"Yesterday, people were in France defending civil liberties. We must equally defend them in this country, even when they are under pressure."
Earlier, Mr Cameron was briefed by intelligence and security chiefs on the current threat to the UK in the wake of the Paris attacks.
Following the talks in Downing Street, a No 10 spokesman said that future counter-terrorism exercises by the police and security services will include scenarios similar to what happened in the French capital.
"The relevant police and agencies regularly carry out exercises to test their response to a terror attack, including scenarios similar to the incidents in Paris," a spokesman said.
"The meeting agreed that for future exercises, the relevant agencies should identify whether there are any further specific elements of the Paris attack that should be built into the exercise scenarios.
Mr Cameron, who joined French president Francoise Hollande and more than a million marchers on the streets of Paris in a unity rally yesterday, emphasised the need for the police to be able to call on military assistance in the event of a major emergency.
He also stressed the importance of international co-operation to prevent the cross-border smuggling of firearms and other weapons.
"The Prime Minister also asked the police and military to continue to work closely together to ensure that the police can call on appropriate military assistance when required across the country," the spokesman said.
"They also discussed the risk posed by firearms, agreeing that our existing tough firearms laws are a very important part of the protections we have and that we should step up our efforts with other countries to crack down on the illegal smuggling of weapons across borders."
Nigel Farage said countries had "turned a blind eye" to unacceptable behaviour among minority communities and must admit culpability in "much of what has happened".
In a debate in the European Parliament on the massacre he also repeated widely criticised claims of a "fifth column" living in Western countries opposed to their ideals.
The Ukip leader said: "We have pursued policies of mass immigration at a rate that has made it frankly impossible for many new communities to integrate and for that I think we have to hold our hands up, and perhaps worst of all we have been guilty of weakness, of lack of courage, of lack of assertion in who we are as people, and we have turned a blind eye within many of our minority communities to practices that would not be tolerated in the rest of the population and indeed we've allowed preachers of hate to go around saying things that are totally unacceptable.
"The result of all this is that we do have, I'm afraid, I'm sad to say, a fifth column that is living within our own countries that is utterly opposed to our values and we how we deal with that problem is vital for the future.
"We must embrace the vast majority of Muslims who themselves are horrified at the civil war that is going on within Islam. But unless we are prepared to admit our own culpability in much of what has happened we are not going to be able to find solutions. I would suggest this though for the future, we are going to have to be a lot braver, and a lot more courageous in standing up for our Judaeo-Christian culture."