Some old parliamentary traditions are pure trimming – like clerks in wigs. Others exist because they work. Round wheels are an old idea, but they have proved to be more effective that the square ones.

And so it is with the concept of parliamentary privilege – the freedom of parliamentarians to protect our rights by making statements and publishing documents in parliament which may be defamatory or libellous if published outside.

Now the South Australian government has made an unprecedented bid to remove the privilege covering recent paedophile allegations made against public officials. The Rann Government rushed legislation into parliament yesterday in the wake of claims by former speaker Peter Lewis and his volunteer “staff” that have ensnared two prominent political figures and two senior police officers – accusations that have not yet been substantiated by hard evidence.

Premier Rann denies the government’s legislation sets a dangerous precedent by restricting free speech. His government has dressed it up as a simple measure to facilitate police investigations. As if.

It’s not standard law and order legislation. It’s an unprecedented rollback of the Westminster tradition, of freedom of speech – and a crass move to scare off Adelaide’s already placid media.

A senior cabinet minister who briefed the media on the bill yesterday admitted it had no sunset clause and admitted that it would create one set of laws for public officials and one for punters. “Come and talk to us,” said the briefer when asked if it would apply to journalists – you’re with us or against us, in other words.

The legislation is likely to make it through the lower house, thanks to tame independents bought off by cabinet posts. The Legislative Council is another matter. Even if it gets through, however, it wouldn’t last five minutes in the High Court. And the allegations can still be aired in any other parliament. So far, Lewis’s and his volunteers’ claims have not stood up.

If truth is on the government’s side, then they should state the truth – not legislate against the freedom to speak it. Suspending privilege – even over one matter – turns Westminster democracy on its head. It’s hard to know whether to describe the legislation – and the spin attached – as shameful or shameless. Actually, it’s both.