No two examples of the Piccadilly Princess Royal Colours will be alike, nor can they be - because each watch is created using a unique hand-picked selection of white and fancy-coloured diamonds which  are individually set to create an unrepeatable, one-off pattern. 

Starting with a simple, 18 carat white gold case, the watch is created by hand-setting 'royal colours' diamonds of no fewer than 66 different colour hues and 10 different cuts on the dial, case and bracelet. Combining the various cuts (Baguette, Cushion, Marquise, Oval, Pear, Princess, Ascher, Emerald, Heart and Round Brilliant Cut) creates an impression of a piece that has been formed by a happy coincidence of nature, almost as if diamonds had been casually scattered across the watch. 

But closer inspection reveals that each of the 225 stones - one to mark every year since Backes & Strauss was founded - has been set in a process taking hundreds of hours of our master craftsmen.

Perhaps more remarkable, however, is the sheer rarity of the diamonds that have been used to create the Princess Royal Colours pieces. 

To yield only a one carat diamond, it is necessary to blast, crush, process and X-ray more than 250 tons of rock; each year, more than 120 million carats are mined, but just a quarter of this quantity is of sufficient quality to be used in the making of jewellery - and, of this, only one in 10 thousand carats is a natural coloured diamonds.