Kevin Rudd and Peta Credlin

If you want to stop Sky News Australia's stream of misinformation and crackpot conspiracies you need to go hard, go early and above all get a lawyer. Go to the regulator? Forget it.

That's the lesson from an on-air apology delivered last night by Sky presenter Peta Credlin, who was forced to retract claims she had made about former prime minister Kevin Rudd.

Credlin, the powerful Liberal Party figure who perversely has her own platform on the Murdoch-owned channel, had accused Rudd of running a "data harvesting exercise" with his online petition last year calling for a royal commission into the Murdoch media. The petition attracted more than 500,000 signatures, lodged by email.