David Cameron and Nick Clegg need to think less about the election, and more about how we can actually protect ourselves against terrorism

The Paris march this weekend showed powerful determination from across the world that we will not let terror win. Beyond the grief and the bravery of those in Paris, there must be a long campaign to defeat extremist ideas, prevent young people being drawn into hatred, stop those who pose a threat, and maintain the cohesion of our communities. And more needs to be done.

But here in Britain the debate is at risk of slipping into a caricatured pre-election row between David Cameron and Nick Clegg over communications data. It doesn’t help, and risks making it harder to get the action we need on the streets and online to defend both security and liberty against extremist threats.

The Prime Minister has said that the Conservatives will bring back the original Communications Data bill from four years ago, and that anything else will put security at risk. Meanwhile, the Deputy Prime Minister warns us that the agencies will end up tracking grannies surfing garden centre websites and changing the law will destroy our precious liberties.

Neither are right. The original bill was too widely drawn and put too much power personally in the hands of the Home Secretary. But the current law is failing to keep up with changing technology as both the current powers and the current safeguards are increasingly out of date. No one wants the state to track pensioners in garden centres, but they do want them to be able to stop terrorists who may be planning attacks. Reforms are needed. But changing powers need new safeguards and oversight so they can’t be abused.

That’s why last July we called for David Anderson, the independent reviewer of terrorism legislation, to review the law and set out detailed proposals for reform – looking at both capabilities and checks and balances. Both Tories and Liberal Democrats supported that review at the time and it is due to report shortly. But election pressures mean they have reverted to caricatures instead.

The Prime Minister and Deputy Prime Minister are colluding to persuade us that there is a binary choice between protecting security and defending liberty – that the Tories have chosen the first, the Liberal Democrats the second, and the public must choose too.

But both caricature and choice are misleading. In practice, the Conservatives weakened counter terror powers when they abolished control orders and cut back Prevent in 2011. And in practice the Liberal Democrats backed new powers in the latest legislation without any proper judicial safeguards.

The choice is false too. Liberty and security depend upon each other. On that first day in Paris, terrorists targeted writers and police officers - the embodiment of free expression and the embodiment of state protection. The editor of Charlie Hebdo, and the police protection officer employed by the state to keep him safe to exercise free speech were gunned down side by side.

So we need a more sensible – and more detailed – debate than the one offered us by David Cameron and Nick Clegg. We need proposals from David Anderson to help the authorities track terrorists whilst protecting everyone else. And we need wider action too.

Stronger controls are needed on those who pose a threat – including prosecutions and using powers that already exist or are being debated in Parliament now. None of the estimated 300 British citizens returning from the Syrian conflict have been placed under the restrictions of special counter terror powers TPIMs. Why not? They should be reassessed. Most of those returning are not required to join deradicalisation programmes. Why not? It should be compulsory.

But perhaps most important of all, much more needs to be done to strengthen the Prevent programme and stop young people being drawn into hatred in the first place. Prevent should be supporting community led action, not just police action, to challenge extremism. Too many young people are being recruited and radicalised through social media now, and much more could be done to counter and challenge those vile views. In the end our strongest defence against extremists is a cohesive society that promotes strong values and will not let hatred take root.

Defeating terrorism means defending both liberty and security, on the streets and online. It needs shared purpose and thoughtful debate, and we should all maintain that no matter how the election pressures grow.