LAST Thursday there was an incident on Radio 4 which surely qualifies as one of those great broadcasting moments. Patrick Muirhead was reading the eight o'clock news when he was interrupted by an electronic rendition of Auld Lang Syne.

He continued unflustered for a moment before apologising and telling the listeners that someone had left their mobile phone in the studio. He then switched the thing off and started the news again.

Some people will suspect it might have been his own phone that was intruding into the broadcast. If so, I think he still deserves credit for the way he handled it.

Judging by the way people behave in everyday life, it would have been not at all surprising if he had answered the call and said "Yeah, hello. I'm just reading the news, but go on."

If mobile phones are here to stay, we're going to have to agree on some etiquette.

It ought to go without saying that it is not acceptable to make calls while attempting to drive a car. But there are a few other circumstances where we could also try to ban them. Firstly, places of entertainment.

I have heard people call their partners from a cinema to let them know that the film was nearly over and they would soon be ready for their lift home. If you do this sort of thing, may you be condemned forever to watch the films of Michael Winner.

Secondly, the supermarket checkout. It may seem to you that queuing is wasted time, but if you're nattering to your friends while your goods are going down the conveyor belt, with the result that the cashier is ready for your money and you haven't even started packing yet, you are wasting the time of everyone else in the queue.

Thirdly, public transport. I have no idea why it's easy to ignore two people having a conversation next to you, yet impossible to disregard someone at the other end of the railway carriage talking on their mobile. But it is.

Fourthly, any occasion when you have an appointment with someone. They've booked your time and are entitled not to have the conversation interrupted by someone who only thought about contacting you 10 seconds ago.

And, finally for now, any occasion when you're walking down the street within earshot of other people. When I'm ambling along and someone nearby suddenly says "Hi", I react in one of two ways.

If they're approaching me from behind, I leap several feet into the air in surprise. If they're coming towards me, I assume they must know me from somewhere and I smile and pretend to recognise them. Either way, you feel a bit of a nit.