At the end of it all, things settle, and there on the canvas is the image – the skid-mark of the impact, so to speak.What I’m getting at is that Bacon did half-want to elide the act of painting. The above line of thought is quite wrong; the existence of the drawings damages the painting not at all. But on the other hand, Bacon himself probably believed something rather like that, and it was a reason for him to deny his drawings. After all, the Bacon myth, partly self-constructed, tends to picture the artist as fighting drunk, flinging himself and several pots of paint at the canvas.

For didn’t he always claim to work in an entirely unplanned and quasi-random manner? And doesn’t the power of his art involve a sense of this spontaneity? But these studies and try-outs sink that story – and expose the painting as a kind of con That’s the dreadful secret they reveal.Not quite But it is a slightly difficult issue I think the right answer goes like this. By denying them, Bacon was really trying to deny the fact that he had a creative process at all. And what’s suggested is that discovery of these drawings touches his paintings very damagingly. And it’s not that Bacon mightn’t have had good reasons for keeping his drawings quiet. As David Sylvester says in his preface, he probably didn’t think they were much good in themselves, and he didn’t want to encourage an irrelevant interest in his creative process, as opposed to his paintings.Fine But he may have had bad reasons, too.

It wasn’t just that the old dog had been caught telling lies No one could be surprised or shocked by that, as such. All we get is a tiny mention in the catalogue – “substantial quantities of comparable material have recently been attributed to the artist” – a briskness that suggests the issue remains tricky.The TV programme, of course, and others, too, have gone on to suggest that the existence of any Bacon drawings is more than tricky, it’s damned awkward. Whatever value that might give them, it seems likely that many visitors will have seen the programme, and could do with more information here. But now it’s thought possible that this other hand belonged to Bacon’s boyfriend of the time, and that the drawings aren’t so much inauthentic as collaborative. But these, it was said, the Tate had at one point taken an interest in – they were offered without charge, apparently – but then the gallery got cold feet, and the affair was made to sound mysterious and conspiratorial, as if the Tate wanted to hush up the very existence of these pictures.The problem, I gather, is that another, non-Bacon hand had been detected in the pictures, and that made them dodgy. And if you’re looking for revelations, you have to see them in quite another way.You may remember a TV programme on Channel 4 last year about a large haul of these drawings-over-photos, in the possession of a friend of the artist They’re not in this show. But I do say: if we’d known them all along, I don’t think we’d now give them a lot of attention.

They’re often graceful in the way that Bacon himself was graceful. They stress the cartoony side of his art, which is always worth stressing. The fact that he worked on them, too, doesn’t seem such a big difference.I don’t say these drawings lack value or enlightenment. We know from photos of his studio and his interview with David Sylvester that he worked from, and among, torn-out and trampled-on photos – Eisenstein film stills, Muybridge motion studies, fine-art reproductions, natural history shots. And as for the altered photos – well, they’re interesting, because they show Bacon disrupting an existing image, and in his paintings he’s often disrupting his own images – but they’re almost not news. Some of them can be related, and quite closely, to paintings; some not. And though it would be presumptuous to say that they’re just what you would expect Bacon’s drawings to look like, I don’t think anyone seeing them will get a big surprise, or say “wow, so that’s how he drew”.No They figure.