By TAMARA ABRAHAM
Mysterious case: The Duchess of Cambridge was wearing her sapphire engagement ring when she arrived at the Royal Marsden in London yesterday (left) but it had vanished by the time she left two hours later (right)
It is probably the most famous engagement ring in the world. So it didn't take long for a few people to notice that the Duchess of Cambridge's ever-present sapphire and diamond sparkler had mysteriously vanished yesterday.
Catherine, who was with her husband, Prince William, for the opening of a new cancer centre, was wearing the £250,000 Garrard ring, once owned by Princess Diana, when she arrived at the Royal Marsden in south London.
It was a distinctive shock of colour against her oatmeal-coloured Amanda Wakeley dress.
The most famous engagement ring in the world: It didn't take long for a few people to notice that the Duchess of Cambridge's ever-present sapphire and diamond sparkler had vanished
But one inside the hospital, the only jewellery remaining on her left hand was her plain gold wedding band.
Of course, there was a simple explanation for the missing ring. Rather than misplacing it, or making some ill-timed statement about the state of her marriage, the Duchess had simply stowed it in her LK Bennett clutch bag for hygiene reasons on the advice of hospital staff.
Hospital protocol: The Duchess left her ring and clutch in the care of hospital staff for hygiene reasons. The Duke had removed his jacket, tucked away his tie and rolled his sleeves for the same purpose
A palace source told People magazine: 'The plan was always to take it off when she went into the ward in the same way the Duke and palace staff rolled up sleeves and tucked ties into their shirts.'
They revealed that William's jacket and Catherine's clutch were left in the care of hospital staff while they were given a behind-the-scenes tour of the Oak Centre.
And before their audiences with young patients, they followed strict hospital protocol by rubbing antiseptic gel onto their hands.
Sparking form: The Duchess also wore a small silver, diamond-studded cross on a chain and diamond earrings by Kiki McDonough, which she was not required to remove
Elegant: Catherine wore an Amanda Wakeley dress with an LK Bennett clutch and heels for the hospital visit