Mark Steel: It is time to name and shame Leonardo da Vinci

'He had a long-term relationship with a lad called Salai, starting when the boy was 10'

Because I'm the most useless person in the world at drawing, I'm hugely impressed by anyone who can draw at all. When I see the pictures scrawled on the inside of a public toilet door, half of me thinks "That's dreadful" and the other half thinks "How do they get the bend in the legs to look so realistic?".

So it seems at last I have something in common with the Queen. For it was revealed this week that she owns 600 original drawings by Leonardo da Vinci, of which she is kindly allowing 10 to be exhibited in the Golden Jubilee celebrations.

Apparently, they were originally swiped by Charles II. See, they really are like any normal family – unable to go abroad without taking hundreds of pictures. When he first got them, I bet Charles would bore the neighbours by showing them one by one – "This one's of a prototype helicopter, and I think you can just see the bed and breakfast we stayed in the second week."

So the Queen is obviously a fan of Leonardo and has lovingly placed her collection in a vault in Windsor Castle. Though I'm sure the whole family goes down regularly for a viewing, ending with Philip bellowing: "Whatever made the idiot think that thing would fly? Typical dago." Maybe this goes some way to explaining why Prince Charles is so screwed up.

Normally, when a five-year-old presents his or her parents with a crayoned squiggle, they'll say "Oh that's lovely darling" and sellotape it to the fridge door. But Charles must have handed his over and been told: "You think we're going to be impressed by that; we've got six hundred original Leonardos in a downstairs cupboard."

In some ways this is a continuation for Leonardo, as he depended on commissions from the ruling families. But at least the Sforzas, the Borgias and the splendidly titled Lorenzo the Magnificent hired him to do stuff they would display.

Now, 10 drawings will be on display for a year, which is sure to attract an audience because the fascination with Leonardo is his genius in so many different fields. As well as painting the most famous picture ever, he was a pioneer in architecture, engineering, anatomy, geology and botany.

And he was reputed to be the finest player of the lute in the whole of Milan, playing an instrument he made himself out of silver, in the shape of a horse's skull. Which must have made him the world's first heavy metal lute player.

Specially with that robe and long beard, it's almost certain he spent part of his career screaming "ARE YOU READY TO ROCK MILAN?" while fans danced by doing imaginary drawing with "air pencils".

And his anatomical drawings reveal how he discovered the existence of the sphincter, the appendix and the arteries and that the heart is a muscle. Though, most spectacularly, he had this to say about the penis: "It confers with intelligence and sometimes has intelligence of itself. Sometimes, although the will of the man desires to stimulate it, it remains obstinate, and sometimes it moves by itself without license from the man. This creature has a life and intelligence separate from man. He should display with ceremony the one he serves."

But there is one fact about him that, above all others, should interest today's media – he had a long-term relationship with a lad called Salai, which started when the boy was 10. So isn't the News of the World being a bit slack here? Surely Leonardo's face should be on a front page that warns of "the sickest drawings ever". Then a crowd of Windsor locals should march to the castle screaming: "Perverts don't deserve our patience/ Send him back to the Renaissance."

There are plenty of things he wouldn't understand about the modern world, not least the distinction between different subjects, especially science and art. For Leonardo, one was unimaginable without the other, to the extent that, while painting for the Medicis, he wrote: "Let no man who is not a mathematician read the elements of my work."

This was the basis of his times, that a new world was being formed in which rational thought would conquer mysticism in all fields. Which is why he also wrote: "We must doubt the certainty of everything that passes through the senses, but how much more we ought to doubt things contrary to the senses, such as the existence of God and the soul."

So we can only imagine how much he would have doubted the right of one family, by birthright, to own almost everything, including the drawings that he created to express his doubt.

Especially as they're valued at countless squillions. Much of his work, after he died, was left in his house, where a lodger looked after it until he moved, when he wheeled the whole lot in a cart to his next address. I love the idea that someone must have seen that bloke pushing his belongings, including a pile of Leonardo's work, along a country lane and thought: "Ah look at that poor sod, that pile of drawings must be all he's got in the world."