'The Last da Vinci Exhibition' at Christie's

Christie's, the auction house, has put on a short, three-day exhibition showing the last painting by Leonardo da Vinci to still be in private hands before it's auctioned in New York. The painting is called 'Salvator Mundi' (Saviour of the World) and shows Christ with one hand raised in blessing and a crystal orb in his other hand. The painting has already been on show in Hong Kong and San Francisco and heads off to New York on Saturday to go on show before being auctioned. The estimated price is $100m so I don't think I'll put in a bid.

It's only recently been authenticated as a Leonardo painting, one of only 20 known paintings by him rather than by his workshop or pupils. It was 'rediscovered' in 2005 and, after six years of research, was unveiled as a Leonardo in 2011 at the National Gallery, London.

That painting will have been x-rayed, studied in infrared, paint samples tested to check the chemical composition matches the paint made around 1500 when it was painted, brush techniques will have been examined and lots of paper records will have been examined to find written, historical provinence. According to Christie's, the earliest reference to it was being in the Royal Collection of Charles I and hung in the private chambers of his wife, Queen Henrietta Maria, in her palace at Greenwich.

 It's only on show in London for three days so I made it along to Christie's in St James's on the last day. Inevitably, there was a queue out the door and around the corner - the lady in the black suit (all employees seemed to be in black suits) said the waiting time was about 30 minutes. In the end, it was probably only 20 minutes. Let in in small groups there was a very orderly British queue through a doorway into one room, then into another, and then, round another corner, there it was on the wall with a single spotlight and two guards either side. Surprisingly, we were allowed to take photos without flash so I did.

The painting's not very big, probably about life-sized of head and shoulders, and there's a definite touch of the 'Mona Lisa' in the face. The painting is delicate and precise, with Christ's hair in ringlets and he seems to be wearing some kind of tunic rather the robes he's usually painted in.

We weren't allowed to stand in front of the painting for very long - almost close enough to touch - before being asked to move on so others could have their 30 seconds. I used some of my time to look at the frame which reminded me of the frame for the Fra Angelico 'Virgin & Child' in the Rijksmuseum in Amersterdam - it's obviously a different colour, shape and design but I couldn't shake the lingering memory.

I'm pleased I saw it since I'll probably never have the opportunity to see it again. I hope it goes into a public collection somewhere and not just some rich person's bank vault. Thanks for the show Christie's.