Journalists must protect their sources. From whistleblowers revealing great secrets to exposés of everyday corruption and incompetence, few will talk if they fear they will lose their jobs or maybe more than their jobs. The police might arrest and jail them. In extreme cases, dictatorships or terrorists might kill them. Livelihood, liberty, life – all can be endangered when sources speak out.

The powerful sympathise. Lord Justice Leveson, Ed Miliband, Nick Clegg, David Cameron and the celebrities and media academics of Hacked Off have always said that they just wanted to stamp out abuses of media power, not investigative journalism. Leveson intoned that a free press was a “cornerstone” of our democracy. Politicians declared they wanted to “safeguard and promote good investigative journalism”, as Miliband put it. There was nothing to worry about, nothing at all. Millions of otherwise sensible people believed them.

Let me dispense with euphemism. The attacks on confidential sources and public-interest journalism by the secret police and Crown Prosecution Service are so severe, they prove that the assurances given after the hacking scandal were a pack of lies. The authorities have played on an understandable but disastrous confusion in progressive thinking. The tabloids are scummy and Rupert Murdoch is sinister, it runs.

Who wants to be on the side of vicious men who have wasted what little talent they had stalking celebrities? The only answer to this question is “no decent person”. Ask who wants to be on the same side as Murdoch and you receive the same reply. They were so wrapped up in their righteousness that they did not notice that the state was thanking them for their gullibility and seizing the chance to lock down and shut up.

All of those who thought that by going along with Hugh Grant they were making a stand against the Murdochracy ought to look at how Murdoch and the criminal justice system aren’t enemies but allies.

Murdoch’s great fear was that the hacking scandal would lead to a corporate prosecution of News International. As the journalists who hacked the phone of Milly Dowler and made Sienna Miller’s life a misery worked for News International, and as the executives of News International justified their princely incomes by saying that they were responsible for the organisation, a corporate prosecution was indeed essential. It would show that the Crown Prosecution Service wanted to punish the powerful, not just the hired help.

At the trial of six Sun journalists, which ended last week with the jury acquitting two and failing to reach a verdict on the other four, defence lawyers quoted Gerson Zweifach, News Corp’s general counsel. He feared a corporate prosecution of News International in the UK would destroy its American interests. (The US authorities are a little more willing to punish wrongdoing than the indolent Brits.) He had emergency talks with the Met in 2012. According to Scotland Yard, he told the police: “The downstream effects of a prosecution would be apocalyptic. The US authorities’ reaction would put the whole business at risk.” If you can get past his atrocious jargon – why can’t the managers of communications business communicate? – you will hear the panic in his voice.

He need not have worried. Murdoch cut a deal to save his wizened hide. The police had no more right to go into his offices on a fishing expedition than they have to come into your home. They would have needed a reasonable suspicion and a search warrant. Murdoch spared them the inconvenience. The team behind his clean-up campaign went through company records and threw out journalists and journalist sources to keep the cops happy.

Honourable reporters go to prison to protect their sources. Murdoch and his team sent their sources to prison to protect themselves and have tried to do the same to their journalists. As Nigel Rumfitt, QC for one of the six Sun journalists Murdoch tossed overboard, told Kingston Crown Court, the company had been “engaged in a wholesale cover-up for more senior people at the expense of the more junior”. Nothing that was divulged implicated editors of the Sun, current and past. Instead, he went for dispensable employees, who had made the mistake of putting their trust in him.

News International was like a copper’s nark, Rumfitt continued, but the case of Murdoch stood out because the prosecution allowed the informant to run the investigation. “The police can’t even get access to the documents controlled by News International. This prosecution was controlled and instigated by the prime suspect. It has been taken for a ride by a foreign-owned corporation of enormous power, influence and greed.”

Just so. But the British authorities are more than the dupes of corporate power. They have their own “agendas”, as we say. The Sun journalists were not accused of hacking but of paying public servants for stories, including stories that were clearly in the public interest: the Ministry of Defence giving soldiers in Afghanistan faulty rifles, and the revelation that the officer the police chose to liaise with the families of the schoolgirls Ian Huntley murdered was a consumer of paedophile porn. All for nothing. Despite spending millions more than they would on serious crime, prosecutors have yet to convict a Sun reporter.

The fear I had when I first read Leveson’s ill-thought-out report is now real. The authorities want to stop the public knowing what they ought to have a right to know. And it is not only the police doing it. As my colleague James Ball of the Guardian revealed, GCHQ routinely hacks British and foreign journalists’ emails and regards reporters producing “exposés either for profit or what they deem to be of the public interest” as a threat to the state only just behind terrorists.

Much needs to be done. Those liberals who followed Grant could make a fair start by engaging in overdue self-criticism. You assumed no dangers lay ahead. You must now accept that you were conned.

Here’s how. Imagine you are a potential source. You will have read of Murdoch’s team naming names, of the willingness of the spooks to treat legitimate public inquiry as a crime and perhaps, too, of the police agreeing to try to stand up a desperate defence of that proved liar Chris Huhne by seizing all the confidential phone records of the Mail on Sunday newsdesk. You have digested the reports and understood what they foretell. You are going to stay silent, aren’t you?