Last week the Home Secretary claimed that anyone who opposes the Draft Communications Data Bill, dubbed the Snoopers Charter, was supporting paedophiles and terrorists.

She argued, “Criminals, terrorists and paedophiles will want MPs to vote against this bill. Victims of crime, police and the public will want them to vote for it. It’s a question of whose side you’re on.”

We’ve heard that argument before. Tony Blair used similar arguments to support 90 day detention without trial, ID cards and invading Iraq.

They were misleading then, and they are misleading now. But they are the signs of someone without rational argument to make.

The Bill gives huge powers to the Home Secretary to require information to be kept about every phone call you make, text you send, facebook image you like, and anything else. Whether you communicate by Skype, Twitter, World of Warcraft in-game mail or post, she wanted to have the powers to access information about it.

We as a party said no. Nick insisted that the Bill not be pushed through Parliament, but be published and discussed, to see if it was the right thing to do – and since then, I and (Lord) Paul Strasberger have been sitting on a cross-party cross-house Committee, going through it carefully.

Today, we have published a unanimous report on the Bill.

I’ve written an article for the Independent on it – it says:

We have gone through the Home Office proposals – and the results are damning. The Bill as it is simply cannot proceed.

… the Home Office proposals go way beyond the current rules with virtually no safeguards, asking for powers for the Home Secretary to insist on any information about any communications being kept, via secret notices.

Our committee has looked into this, and concludes ‘the draft Bill pays insufficient attention to the duty to respect the right to privacy, and goes much further than it need or should’.

It was shocking to me just how little effort the Home Office made to work through their proposals with the mobile phone companies and the Facebooks and the Googles. They didn’t bother to consult properly, assuming that discussions they’d had in 2009 on similar proposals by the Labour government would suffice. And they failed to talk through the details with the Commissioners here in the UK who would have to supervise the system.

These proposals are incredibly expensive too. The Home Office estimate is that they would cost a huge £1.8 billion, and the Committee had little faith that the cost would stay there, given the experience of other IT projects. It beggars belief that this amount of money was being committed with so little evidence at a time like this.

And while the Home Office claimed there would be large financial benefits, they were entirely incapable of providing evidence that this would be the case. As the report says ‘the estimated net benefit figure is fanciful and misleading’ and ‘none of our witnesses could provide specific evidence of significant numbers of lives saved to date’.

The Committee also heard of how broadly the powers would be used. While the Home Secretary claimed in the Sun that ‘Only suspected terrorists, paedophiles or serious criminals will be investigated’, the truth is as that it could also be used for speeding offences, flytipping and things as vague as being in ‘the interests of the economic well-being of the United Kingdom’. We are all suspects under this bill.

Towards the end of the evidence sessions, we began to get a bit more of an understanding of what the Home Office actually want. For example, proper IP address matching would allow the existing system to work better. We could look at measures such as that, but only with proper safeguards.

However what the Home Office asked for was indeed a snoopers charter, which we were asked to support with virtually no evidence.

The Bill in its current form simply cannot proceed. We must find a way forward which increases current safeguards, is narrower in scope and has a far better understanding of the technical challenges we face.

Our lives are moving online. It would be ridiculous for the Government to be given a blanket power to watch over us, just as it would be ridiculous for us to stop the Government from ever accessing any communications data. The proposals got the balance between liberty and security utterly wrong.

If the Home Office wants to fiddle with online surveillance, they have to give us evidence that it’s needed, they have to provide a costed policy, they have to improve the existing system under RIPA and they have to bring in strict and proper safeguards.

As Nick said today, “We cannot proceed with this bill and we have to go back to the drawing board.”

* Julian Huppert was the Liberal Democrat MP for Cambridge from 2010-15