As with all intrusions into British people's privacy, the surveillance powers being proposed by Theresa May today are justified on the grounds of defeating terrorism. Occasionally paedophilia makes an appearance as well, but generally it's a terror argument.

So it's worth considering for a moment how profoundly ineffective these measures are when dealing with terrorism. If media reports are accurate – the full proposal will finally be unveiled this afternoon in the Commons after extensive briefings over the last two weeks - the government has dropped plans to ban encryption technology. There's good reason for that. Doing so would mean that either companies like Amazon and Apple, which use encryption, would have to drop it because David Cameron said so. Or, more likely, they would stop operating in the UK.

It was, of course, tosh. Cameron blurted out some authoritarian rubbish about how important it was that the state could see people's communications and only bothered to check whether it was possible afterwards. It wasn't.

It's a running theme with the prime minister and technology. He did the same thing with promising to prevent children accessing pornography. It's not technologically possible. He might as well have promised to invent unicorns or that it wouldn't rain on your birthday. But Cameron prioritises the public impact of a statement over its content.

Encryption software is produced by firms all over the world. They are not subject to British law. And they're not, as the Home Office seems to hope, likely to spend all this time creating encryption software only to allow the security agencies to chuck in a bit of code at the back giving them access. And there's no point saying that the government can stop Brits downloading the encryption software. Browsers like Tor, which bounce users around the world as they access the internet, mean we really can't prevent Brits from accessing the software unless we ban laptops.

David Anderson, the independent reviewer of terror laws, was particularly concerned about encryption software and the way it operated in the dark net to create an ungoverned space. There's no technological solution to that and there is no legal solution either. The only solution, and it is not a very good one, is diplomatic. You have to convince these companies to work with you.

Anderson noted that firms in Silicon Valley, say, might be more willing to cooperate if the British system more closely resembled the American one. That involves bolstering its judicial oversight, which anyway would be no bad thing. There have been some minor concessions in that regard, with the government saying it would have a team of ten senior judges rubber-stamping surveillance warrants. But Anderson's moderate proposal that the power to issue warrants was removed from the home secretary and handed to the judiciary was rejected.

This is not radical stuff. Having a home secretary sign off on these warrants is completely archaic. They don't do it in Europe. They don't do it in the 'five eyes' countries like the US, Canada and Australia who we share information with. And for good reason. May signed off on 2,345 intercept warrants in 2014 alone. Either they were not properly scrutinised, or she was failing to give her other responsibilities appropriate attention. The current system just doesn't make sense and justifying it by constantly referring to judges as 'unelected', as ministers have done, will not make any more sense.

Even on this minor issue, the Home Office wasn't prepared to compromise in order to convince foreign firms to cooperate. On the actual ways in which people can operate secretly online, they have done nothing. Instead, they are casting their net far and wide in the areas where the majority of non-terrorists operate: the mainstream internet and normal internet usage.

Communications companies will apparently be required to store records of customers' phone and internet use for a year, according to the briefings given to the press. Police will be able to access people's internet connection records, a power currently banned in the US and all of Europe.

GCHQ's existing powers will be enshrined in law, including those allowing it to sweep up the contents of a laptop or smartphone, to track your location, listen in on your calls, or take photos of the people around a device.

Authorities' power to see which websites you've been visiting will also be present. Anderson was very sceptical about this, insisting that a "detailed operational case" needed to be made with a "rigorous assessment" of its lawfulness. That hasn't happened, but the proposal seems to have made its way into the bill anyway.

These measures will affect the public but not the terrorists. Any terrorist capable of carrying out a terror attack knows how to use Tor, or encryption software, or a library computer, or an internet cafe. They are not organising terror attacks on Facebook Messenger.

These moves are not aimed at terrorists. They are aimed at us. This is a programme for the mass surveillance of the British public. Terrorism is just an excuse.