London: The Conservatives would bring in a law to help the security services spy on the activity of British citizens on the internet in the wake of the Paris attacks, David Cameron has said.

The Prime Minister said the Security Services would be given the powers to read all messages sent over the internet, if his party wins the general election.

Cameron’s decision means that the so-called “snoopers’ charter” is emerging as a key election battleground with the Liberal Democrats opposing the plans, making it a “red line” issue if another Coalition is formed.

More power for spooks

Labour is backing more powers for the intelligence agencies, as long as the powers are aligned with stronger oversight of their activities.

Nick Clegg, the Liberal Democrat leader and deputy Prime Minister, will say in a speech on Tuesday that it would mean “a new indiscriminate power for governments to record every man, woman and child’s web history, emails and social media interactions” whether they are innocent or guilty.

He will say: “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 have been blocked by Liberal Democrat opposition in the Coalition. However, the police and the intelligence agencies have expressed concerns that they are not able to access the content of some of the new ways to communicate over the internet. Clegg also criticised Cameron for his promise to protect free speech after the Paris massacre. He said: “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.”

Cameron said any new law would be in force from next year. He said: “If I am prime minister I will make sure that it is a comprehensive piece of legislation that does not allow terrorists safe space to communicate with each other.”

The news came as Cameron said British soldiers were on standby to take to the streets in the event of a Paris-style gun attack by terrorists. The Ministry of Defence has been told to ensure troops can be deployed if needed if extremists strike in the UK. It is understood British special forces, such as the SAS, would be the first to be called in to action but the possibility of regular soldiers taking to the streets has not been ruled out. The Prime Minister ordered the police and military to work closely “to ensure that the police can call on appropriate military assistance when required”. Cameron met security, intelligence and policing chiefs on Monday to assess the risk to Britain following the three-day terror outrage. The Paris scenario will be re-enacted in exercises in the UK, designed to prepare for a terror attack.