The leaking of coordination comments on the FuelWatch Cabinet submission is worrying the Rudd government – with good reason.

Ministers leak frequently – Sir Humphrey in Yes Minister notes “The ship of state, Bernard, is the only ship that leaks from the top.” In the lead-up to the budget there is almost a roster: leak A to the Fairfax press, leak B to Channel 7, leak C to News Ltd, etc. It is an accepted element of Australian politics.

This leak is different because apparently it comes from the bureaucracy; we know this because Laurie Oakes, instead of just an enigmatic denial of all knowledge, actually confirmed it had not come from a Minister.

There are five types of leaks from the public service.

The first is accidental. An official from Treasury leaves a confidential brief at a meeting; someone from Defence leaves a sensitive inquiry file inside a Qantas lounge computer. Acutely embarrassing for all concerned, but not fatal – mistakes happen.

The second is the lunatic anarchist bomb thrower leak: simply to cause damage. We see this occasionally in the security agencies, where an unstable agent cracks under the pressure of keeping secrets.

The third is the leak of genuinely important information about wrongdoing by a senior official or Minister – corruption or malfeasance in high office. This kind of leak is less common with the introduction of whistleblower legislation or procedures: if a public servant does have evidence of wrongdoing, there are often (although not always) means to bring these to light.

Fourth is a leak motivated by a genuine policy concern. A public servant becomes so concerned about the policy directions being taken by government that he or she feels compelled to leak information to try to sway the debate, or so appalled by wrong information that there is a need to set the record straight.

The classic case was in 1984 when British civil servant Clive Ponting leaked classified information about the sinking of the Argentine ship the General Belgrano in the Malvinas/Falklands war, exposing misleading government reports of the affair. The jury in his trial acquitted him of a breach of the Official Secrets Act, saying he had acted in the public interest. Soon after, the British civil service tightened up the rules and removed the public interest defence.

The fifth is politically partisan – a public servant has an opposite political leaning from the government of the day and wants to give ammunition to the Opposition. Many of the senior ranks of the public service today were hand-picked by Howard or his office for their demonstrated loyalty, so naturally there is some suspicion.

The terrifying possibility for the government is that this recent leak is a combination of two and five – a politically motivated leak (it certainly looks like that) from someone so disaffected that they just don’t care. If that is the case, this won’t be their last leak by any means.