Turn it off!

For performers and audience alike, it is one of the most maddening features of modern life.

In theatre or cinema, invariably at a dramatic moment, someone's mobile phone goes off.

Until now, the culprit's only punishment has been the glares of those whose enjoyment has been shattered. But a law likely to be introduced in New York City will change all that.

Anyone leaving a mobile on during an indoor performance of a film, play or concert faces a £30 penalty.

The legislation is being proposed by a member of the city council, Philip Reed. ' Public performances offer audiences a welcome escape from the rigours and gadgets of everyday life, while ringing cellphones and loud, one-sided conversations offer only headaches,' he said.

Mr Reed does not envisage police spending all their time ticketing talkers but thinks the law would encourage theatre patrons to deal with those who are less considerate.

'People feel empowered to at least speak up if there's a law that says you can't do this,' he added. 'It's probably the most popular thing that I've ever introduced.'

The law, which is expected to be introduced by the end of the year, has the backing of actors. 'The ringing of cellphones has ruined too many theatrical performances for too many people, audiences and performers alike,' said Barbara Janowitz, from the League of American Theatres and Producers.

Several U.S. states already outlaw phone use while driving because of the safety risk, but the new law is the first to punish phone users for anti-social behaviour.

Travis Larson, from the Cellular Telecommunications and Internet Association, said the legislation was over the top. 'We can't outlaw rude people. We can only hope to educate them.'

In London, Jessica Cargill-Thompson, features editor of Time Out magazine, said there would be little appetite for such fines on this side of the Atlantic. 'Most people get really cross if they are disturbed by mobile phones during a performance.

'However, fining people would be harsh because most people who leave their phones on have genuinely forgotten and are excruciatingly embarrassed if it rings.