David Cameron will on Monday tell Britain’s intelligence chiefs that he will introduce the so-called snooper’s charter after a Tory general election win as he redoubles Britain’s efforts to tackle the “poisonous death cult” of Islamist extremists.

In marked contrast to Ed Miliband, who rejected calls for an immediate revival of the snooper’s charter in the UK in the wake of last week’s terrorist attacks in Paris, the prime minister said he would adopt a “more comprehensive approach” to surveillance than he has done in coalition.

The remarks by the prime minister suggest that surveillance could become a divisive issue at the general election. Miliband said after his own talks with the intelligence chiefs that he would adopt a “cautious and considered” approach in answer to calls for increased surveillance powers for the intelligence agencies.

Cameron will meet the intelligence chiefs to discuss whether Britain needs to step up its response to the extremist threat after the Sunday Times reported that up to 150 jihadis could carry out gun attacks along the lines of the attacks in Paris. Cameron, who was speaking on the steps of the British embassy in Paris after attending what he described as the “unbelievable” unity march in the city, said he would assess with the intelligence agencies Britain’s preparedness for a Mumbai-style “roving firearms terrorist attack”.

Amid such threats, the prime minister said he was in favour of modernising Britain’s rules on interception. He spoke in favour of the data communications bill, known as the snooper’s charter, which would allow the agencies the same level of access to people’s use of emails, internet and social media they currently have to traditional means of communication.

Cameron told ITV News: “We do need to modernise our rules about interception. What we have done passing the recent law is we said that law will automatically fall in 2016 so a future government, whether it is led by me or led by someone else, will have to confront this issue and legislate.

“I have a very simple approach to this issue which is that ever since we faced these terrorist threats it has always been possible, in extremis, with the signature of a warrant from the home secretary, to intercept your communications, my communications, or anyone else, if there is a threat of terrorism. That is applied whether you are sending a letter, whether you are making a phone call, whether you are using a mobile phone, or whether you are using the internet. I think we cannot allow modern forms of communication to be exempt from the ability, in extremis, with a warrant signed by the home secretary, to be exempt from being listened to.

“That is my very clear view and if I am prime minister after the next election I will make sure we legislate accordingly. Obviously we are in a coalition. We have made progress on this issue by passing the new law which makes sure we protect some of the abilities we have to stop terrorists. But as I say, in 2016 when this law comes to an end a future government will have to have a more comprehensive approach and I know absolutely that if I am prime minister I will put that approach in place.”

The prime minister told the BBC of extremist threats: “Tackling this poisonous death cult, this extremist narrative of the violent Islamist extremists, is something for all of us to do. We have to confront it whether we find it in schools or universities or in our communities or even in our prisons.”

Nick Clegg, the Liberal Democrat deputy prime minister, declined to support the data communications bill proposed by the home secretary, Theresa May. The coalition introduced emergency legislation last year – the Data Retention and Investigatory Powers Act – which would oblige internet and phone companies to store their customers’ personal communications data for 12 months and to give access to the police. Labour supported the legislation on the basis that a review would be carried out by David Anderson QC, the independent reviewer of anti-terrorist legislation, and that it would expire next year.

Miliband made clear that he would not support new emergency legislation if it was modelled on the snooper’s charter. He told the Andrew Marr Show on BBC1: “We have got to be cautious and considered in these areas. We insisted, when some emergency legislation was passed last summer, that a proper review was done by the independent reviewer of terrorism.

“Let us take a considered look at this, let us take a considered look at what is necessary for the country to keep us safe and maintain our liberties. On this issue of the security services we should always be looking at and making sure they have got proper resources being deployed properly to counter the threat we face.”

Miliband said he would seek to balance two interests: ensuring the security services have adequate powers and resources while ensuring that liberty is protected. He said: “We have got to look at both areas. We have got to look at do our intelligence services have the tools they need? But equally, do we have the proper oversight to guarantee the liberties of free citizens? After all, one of the things we want to protect most of all here is our freedoms. So we should defend our freedoms, also making sure that the security services have what is necessary to counter that threat and defend that freedom.”