Six months ago, you’d have been forgiven for not knowing what on earth a loom band is. But these brightly-coloured elastic bands have fast become one of the top-ten bestselling toys of all time — thanks to their popularity with adults and children alike.

They can be crocheted together, either by hand or on a small plastic loom, in myriad different ways to form all manner of shapes, from the ubiquitous bracelet to more complicated Santa hats.

Loom band-related goods occupy 41 out of the top 50 positions on Amazon’s toy chart.

Manufacturers are bringing out all manner of spin-offs, including charms and sparkly, glow-in-the-dark and even scented bands, while enterprising fans compete to make the most unusual creations, such as hats, scarves, dog collars, miniature superheroes and an entire nativity scene.

And the official instruction videos posted online have been joined by thousands made by fans explaining how to make bracelets and other designs of varying complexity.

In recent weeks, the likes of David Beckham and the Duchess of Cornwall have eschewed Bond Street’s finest jewellers in favour of their own scruffy-looking bracelets.

Loom bands have assumed a universal appeal far beyond the wildest dreams of the craze’s creator, Malaysia-born Cheong Choon Ng, 45.

Now living in the US, three years ago he saw his daughters Teresa, now 16, and Michelle, 13, making bracelets out of rubber bands and tried to join in.

But his own fingers weren’t dexterous enough so he made a small loom with pins stuck in a piece of wood so he could play along, too.

Inspired by his ad-hoc creation, Ng, an engineer, developed a plastic version and patented it, spending £5,800 of the family’s savings to get it made cheaply in China.

By summer 2011, he was selling kits for $15 (£10) under the name of Rainbow Loom. Each comprised a small plastic loom — measuring 2in by 8in — a crochet hook and 600 multi-coloured mini-rubber bands.

But many toy shops were unwilling to stock them. Ng didn’t find his first customer until the summer of 2012 when an American franchise called Learning Express Toys ordered 24 looms.

They sold out within two days and his business took off.

Four million kits have been sold worldwide and Ng’s company is now worth £80 million.

When the Duchess of Cambridge was pictured in April wearing a red and pink bracelet given to her by a young girl during the royal tour of Australia, sales soared by 300 per cent. Shortly afterwards, her parents Carole and Michael Middleton started selling glittery bands for £2.99 on their Party Pieces website.

Last month Prince William accessorised his smart navy suit with a turquoise and black version, while One Direction singer Harry Styles and television presenter Fearne Cotton have also been pictured in them.

But far more bizarre creations than bracelets are being made. Pupils at St Joseph and St Teresa primary school in Somerset are trying to break the world record for the longest loom band chain — which currently stands at 29,040 foot, higher than Everest.

But, as they have only reached 650ft so far, using 60,000 bands, they’ve still got some way to go.

Incredibly, they can also seriously injure children. Earlier this month a doctor posted a picture online of her son with blue fingers where he’d worn the bands so tightly, they’d nearly cut off his circulation.

But their inventor has no plans to stop and more merchandise is in the pipeline.

And when it all gets too stressful? He relaxes by playing with the creations that made him rich.