Whenever I hear the words national security, I reach for my subscription to Liberty. According to the director general of the National Crime Agency, Keith Bristow, in today’s Guardian, the police need new powers to hack private phone calls and emails. The requested “snoopers’ charter” is needed to find out who is talking to whom so as to catch “serious and organised criminals”, not to mention terrorists. While Bristow accepted that this needed selling to the public, he assumed that the public would agree, once “sold”.

I hope not. There is now a mass of evidence that the police are using, or rather abusing, the ever wider surveillance powers given by successive home secretaries. As with phone tapping of old, the claim is that each intrusion is “personally authorised” by a home secretary or a judge. Every police officer knows this is rubbish.

In two recent cases, the Chris Huhne motoring trial and the “plebgate” Downing Street saga, the police plainly accessed supposedly private records. Neither had anything to do with serious crime, let alone national security. In the Huhne case the accessing followed a specific ban on it from the judge. It was clear that such hacking by the police is considered normal. It was met with waffle from the Home Office, which said a “free press is fundamental to a free society”. The so-called interception and communications commissioner, Sir Paul Kennedy, “launched an inquiry”. I can hear a police officer laughing.

One of the many services performed by Edward Snowden was to show that nothing beyond constant press vigilance will curb “big security” from trampling on civil liberty, even in a democracy. In Britain, the coalition’s appeasement of such trampling means that no whistleblower is safe in talking to a friend, a lawyer, a journalist or, for that matter, anyone via a phone or the internet. Anything said may be available to a potential prosecutor or opponent’s law firm. We are back to the Soviet Union, with private conversation confined to public parks.

There is no threat to British national security that justifies the current bid to erode normal civil liberties. Criminals may be getting more cunning, as they always were, and the police and security services may have to work hard to catch them. But authority seems to have no concept of what constitutes going too far. It has no definition of civil liberty. The powers that be need only mouth “war on terror”, and democracy crumbles before them.