Oftel has issued a warning shot across the bows of rip-off premium rate text message spam merchants. It will order mobile phone networks to disconnect spammers if they ignore a "request" from the premium rate service watchdog ICSTIS to stop offending services.

This is not quite the same as banning mobile phone spam per se, but the Oftel order goes some way towards stamping out spam in its most egregious form. We say some, because, the rip-off premium rate reply fax merchants are operating still in the UK, despite apparent regulation.

So how does the premium rate rip-off work for mobile phones. It's pretty simple, and you have to be pretty simple to fall for it. (But who says laws can't protect the stupid too?)

You get an unsolicited text inviting you to reply -maybe it's a competition you've won that you never entered, or maybe there's an 'adult' (nudge, nudge)chat line you're asked to join. You reply - it's just cost you £ 1.50.

The text message spam scam is a recent variant on tricks practised on landlines, where you get called up by a real live person. You are told to ring up a number to win your prize; you ring, you're kept hanging on the line, all the while racking up premium charges; your prize never arrives. Oftel is extending its powers of serving disconnection to telcos to fixed line premium rate services too.

Numbers beginning 090 are premium lines.