The new craze? It's silly

They are not so much taking the world by the hand; as by the wrist. Welcome to the phenomenon of Silly Bandz: brightly coloured, multi-shaped rubber bands that are poised to become the year's most unlikely global fashion trend – not to mention the cheapest.

Demand for the silicone bands, which are worn on the wrist like a bracelet, has exploded in the US this summer after celebrities started sporting them. Sarah Jessica Parker, the doyenne of novel fashion crazes, was spotted wearing an acid green silicone band among her designer bangles, prompting the fashion magazine Grazia to pronounce that a new "pocket money accessory" had hit Britain's fashion scene.

Other trendsetters who have jumped on the bandwagon include the model Agyness Deyn and her fashion designer friend Henry Holland. The actress Mary-Kate Olsen is another fan, as is the food writer and chef Anthony Bourdain, who demonstrated the cross-gender appeal of the surprise fad when he was photographed for a New York magazine last month sporting a turquoise one on his wrist.

UK companies are now scrambling to import the products, which snap back to their original silicon-moulded shape once they are taken off, spurred by a prediction from the chief merchandising officer at Toys R Us, Karen Dodge, that Silly Bandz could be the "hottest toy of the year".

The US company behind the product, BCP Imports, has seen its annual sales explode to more than $100m (£66m) up from barely $10,000 two years ago. Robert Croak, the company's chief executive and one of America's newest multi-millionaires, said he is shocked by the scale of demand for his bands, which retail at £3.99 for 24, making them worth just 12.5p each. He recently turned down a $10m offer for his company, telling USA Today: "This is the American Dream. This is way too much fun for me to take the money and run."

Michael Smith, chief executive of online retailer Firebox, the first to market Silly Bandz in the UK, said: "We are very confident this will probably be one of our biggest sellers over the summer. I spotted them while I was in Las Vegas at a licensing show and they just seem like one of those wonderfully bizarre, simple crazes that could take off very quickly."

The first UK outlet dedicated to the bands opens tomorrow in Brierley Hill, West Midlands. Nicholas Ellsmore has called his company Silly Billy Bandz to get around any copyright issues.