Mass surveillance sounds like it should work – with all of the information at your disposal, surely you would not miss something as glaring as plans to carry out a terrorist attack or ways to bring more people to your cause, surely that would stick out like a sore thumb?

While this seems to be the Home Office’s justification for the Investigatory Powers Bill (IP Bill), the evidential basis for this is pretty thin. William Binney, ex-Technical Director of the NSA, stated to the joint parliamentary committee on the bill that “this approach costs lives, and has cost lives in Britain because it inundates analysts with too much data. It is 99 per cent useless.”

So the UK Government has been told and has chosen to ignore it.

In 2014 the New America Foundation (NAF) stated: "Surveillance of American phone metadata has had no discernible impact on preventing acts of terrorism."

Further to this, Ray Corrigan of the Open University has done the maths and it doesn’t bode well for mass surveillance: “Even if your magic terrorist-catching machine has a false positive rate of 1 in 1,000 – and no security technology comes anywhere near this – every time you asked it for suspects in the UK it would flag 60,000 innocent people.”

What about questions of cost and the apparent lack of alternatives available to us – where does that get us? The government’s plan for telecommunications providers to store all internet connection records requires a great deal of finance to ensure the operators can store the data this power demands in a safe and secure manner. The Government looks to Denmark for a model to demonstrate the power in action, but unfortunately it did not prove to be workable for the Danish, as identified by Lord Strasburger: "When Denmark tried it they found it was useless and it was scrapped. Two months ago the Danes tried again, using a method almost identical to the one planned by the British government. But when they had the budget checked out by independent consultants they promptly dropped the idea again because of its huge cost."

This huge cost translates to an equivalent cost of £1.2 billion for the UK, which is a large number especially in times of austerity, but what that money could fund elsewhere speaks to the alternatives. Using the conservative estimate of £1bn, the Don’t Spy On Us Coalition remarked: “These costs, which would fall to the Home Office, could be the equivalent cost of employing 3,000 full-time police officers at a time of officer cuts.”

Money that could be spent as part of the IP Bill could be spent to enhance targeted surveillance, capabilities that everyone agrees is vital and a more effective use of the state’s resources. The 2014 NAF report mentioned above goes on to identify the processes that proved effective in the initiation of investigations in terrorism cases in the US, with 17.8 per cent of cases being initiated through a community or family tip-off and 16 per cent being down to the use of an informant. The NSA programmes contained in the study account for only 7.5 per cent of cases combined.

Many of the assailants involved in the recent terror attacks in the west were already known to the security services, including the Belgium bombings, both Paris attacks, the Lee Rigby killing and the Boston Marathon bombing.

Mass surveillance (or suspicionless surveillance, to borrow a phrase from Joanna Cherry QC MP) would not have been necessary to stop these attacks, but a focus on targeted surveillance may have. The wilful blindness to the limitations of mass surveillance threatens to shape the narrative around our response to terrorism and channel resources away from effective alternatives.

We continue to be told that suspicion-less surveillance is the only way we can combat terrorism, and that the haste that has defined the bill’s progression through parliament is in the country’s best interest, despite all the evidence to the contrary. We are unconvinced.

Is the IP Bill nothing more than a gesture, something demonstrating the government’s hard-line stance on terrorism, and conversely the softness of any opposition? If so, the question of effectiveness may be beside the point – it doesn’t have to work, it just has to look like it does. If we are to defeat terrorism, we should depend on tools that work; processes that are chosen for their efficacy as opposed to what they look like.

Nik Williams is Policy Advisor at Scottish PEN.