Every 73 seconds, police use snooping powers to access our personal records. Who’ll rein them in?

At its peak, the Stasi employed one agent for every 165 East Germans. Spying was a labour-intensive business then — you needed to monitor telephone calls, steam open mail, plant a bug, follow suspects on shopping trips and then write reports for the KGB. The advantage was that, human nature being what it is, the Stasi would probably succeed in gathering dirt on all but the most saintly. The drawback: trying to gather files on so many millions could almost bankrupt a government.

How much easier it is nowadays. By interrogating someone’s mobile phone, the police can gather more information than the Stasi could dream of compiling. The modern smartphone contains all the secrets of a life: bank balances, emails to lawyers, texts to lovers. There are apps for gambling addiction, even pregnancy advice. Your phone knows how fast you’ve driven and where you’ve been — not just within a town, but within a room. All this can be used as evidence against you, should the authorities find it useful.

This is why the unfolding scandal of police hacking journalists’ phones matters. Like the media phone-hacking scandal that led to the Leveson inquiry, it offers a glimpse into an abuse of power that doubtless involves far more victims. Phone hacking arose when private detectives realised that new technology allowed them to hack into the voicemails of victims. With police hacking, the bobbies worked out that new technology and new laws let them ask for the phone records of any journalist — they no longer had to go through the tiresome ritual of asking ‘Who’s your source?’ and being told to get stuffed. They could just grab the journalists’ phone records and work it out for themselves.

The first such case that came to light involved Tom Newton Dunn, political editor of the Sun.