Fans of the new technological craze known as flash-mobbing are preparing to launch three surprise invasions in Sussex.

Flash mob events - mass gatherings organised by email and mobile phone - have already caused confusion, amusement and frustration in New York, London and Rome.

Brighton, Worthing and Crawley are now being targeted by internet pranksters, who are threatening to strike any day now.

Flash mobs, which started in New York in June, are large crowds of strangers who are ordered to meet at a certain time and place and act out specific instructions.

The first event was held at Macy's department store in New York, when a flash mob gathered at the ninth-floor rug department and stood around discussing carpets, before leaving.

About 200 people congregated in a small sofa shop in Soho earlier this month, spent seven minutes praising the furniture on display and then dispersed.

In Germany, 40 Berliners simultaneously reached for their mobile phones and began shouting "Yes! Yes!" in English.

Supporters claim the craze is fun, apolitical and spontaneous but critics have called it a waste of time and energy.

People are being invited to join the Sussex flash mobs by going to www.angelfire.com/super2/sussexflashmob Subscribers are promised an email three days before a flash mob event, revealing where to meet and what to do.

One of the Sussex organisers said: "Brighton is about to become one of the first on the South Coast. And it could happen anywhere - shop, street, you name it."