That's something they wouldn't have had to do before last year. But then, the warrants aren't much of a safeguard, because we don't know whether they were asked for or granted. We're not allowed to know. In the Kafkaesque world the politicians of both major parties have allowed Australia to become, anyone who tells us can go to prison for two years. But the real problem with the raids is worse. Though no one seems to have noticed it, the AFP is trying to use very old laws to pursue not just the suspected leaker, but the recipients of the leaked documents. A redacted version of the search warrant that authorised the police raids in Melbourne was posted over a week ago by the ABC's Media Watch program. Yet, so far as I'm aware, no one has pointed out what a truly alarming document it is. The warrant justifies the searches on the grounds that two separate offences might have been committed. The first is that "in an as yet unidentified place an as yet unidentified Commonwealth officer communicated documents relating to the National Broadband Network to [redacted name] contrary to subsection 70(1) of the Crimes Act". Now section 70 is short, and notorious: it makes it an offence, punishable by two years' imprisonment, for a "Commonwealth officer" to communicate any information that he or she comes by in the course of their duties to anyone who is not authorised to receive it.

According to the Crimes Act, a "Commonwealth officer" includes "for the purposes of section 70, a person who, although not … employed by the Commonwealth … performs services for or on behalf of the Commonwealth". And that, at least according to the AFP's lawyers, includes an employee of the NBN Co. So, in our brave new world, someone proven to have leaked a document about how the nation's most expensive infrastructure rollout is being managed, regardless of whether the leak is or isn't in the public interest (for no such test applies), can be thrown into the slammer for two years. But it gets much worse. Because the second offence the AFP was investigating, according to the search warrant, is that "[redacted name] did receive documents knowing at the time he was not authorised to receive the documents, contrary to section 79(6) of the Crimes Act". The suspected criminal in this case is not the leaker, but the recipient of the leak. Section 79 is headed "official secrets". It is concerned primarily with preventing the unauthorised disclosure to third parties of information relating to defence and national security. But its phrasing is broad. It states that a "prescribed document" is one that a Commonwealth officer obtains and which "by reason of its nature … or for any other reason, it is his or her duty to treat as secret".

Now, in law, there's a difference between having an obligation to keep something confidential, and having a duty to keep it secret. "Secret" is a heavy word. Yet the AFP search warrant claims that background briefing documents about the rollout of the NBN are "secret", and that as a consequence anyone who can be proved to have received them, knowing that they weren't authorised to do so, can be thrown into the slammer for two years, just like their source. This is extraordinary, and to my knowledge, unprecedented. We now have a federal police force that believes that journalists or (in this case) political staffers who are leaked documents by an employee of a Government Business Enterprise may be committing an offence – no matter what the public interest in disclosure may be, no matter what the documents' contents, and no matter whether or not the recipient staffer or journalist discloses them to anyone else. As one of the lawyers I consulted wrote to me: "I have never heard of anything so crazy … It's ridiculous they got a search warrant partly on that basis." But they did. These days, it seems, the police and security forces can get just about anything they want, even when the issue has nothing to do with national security. I said a year ago in this space that Australia is on the way to creating a secret police. This, I'm told, is to be my last regular column for Fairfax Media. But here, or elsewhere, I'll try to keep tabs on our ever-diminishing freedoms.

We all should.