It's called 'Juste un Clou', or 'just a nail' – despite the fact that it's made from gold. Predictably, the nail is a revived idea from the 1970s, having originally been conceived by the legendary Italian jewellery designer, Aldo Cipullo, for Cartier New York at a time when Studio 54 was the place to be seen and Andy Warhol was everyone's darling.

Cipullo was on something of a roll at the time, having created the Cartier 'Love' bracelet in 1969. This inspired piece was based on the chastity belt and was supplied with a screwdriver, the idea being that the giver attached it to his or her lover, tightened up the screw and left the bracelet there for good – so symbolising the eternal nature of the relationship.

Being something of a smart marketeer, Cipullo recommended that couples bought the bracelets in pairs and, at first, they were made available only to celebrity couples such as Richard Burton and Elizabeth Taylor; but instant demand led to the Love bracelets being offered to the public at large and they have remained a Cartier best-seller ever since.

The Clou, meanwhile, was Cipullo's way of turning an everyday object into a thing of beauty. Original '70s versions occasionally appear at auction and, up until now, have been relatively affordable. The arrival of the 'new Clou', however, will surely see values spiral, not least because the starting price of the 21st Century version is £4,200 in yellow gold, more for white or red gold versions and more still for those which are set with diamonds around the head and tip.

Available in large and small sizes (and as a ring), the Clou is most definitely 'unisex' and will undoubtedly be seen on the wrists of the international jet set alongside their trendy friendship bracelets and luxury watches.

Just a nail? Hardly.

Photos: Cartier