Why it is worth fighting to save this painting

The question of whether works of art should be allowed to leave the country is perhaps not as simple as is commonly assumed. The almost universal belief seems to be that once you've got hold of something, you damned well hang on to it, and it would be a tragedy to lose it to a foreign museum.

The question of whether works of art should be allowed to leave the country is perhaps not as simple as is commonly assumed. The almost universal belief seems to be that once you've got hold of something, you damned well hang on to it, and it would be a tragedy to lose it to a foreign museum.

This may often be a good working principle, but it shouldn't always be adhered to. It is, for instance, not always and unarguably true that works of art ought to stay in the country where they were produced. Although I personally think that the Parthenon marbles were acquired improperly and would now make much more sense in an Athens museum, it would be unwise to start acceding to requests to return the Rosetta Stone to Egypt, or African treasures to their places of origin. Those cultures are probably much better served by being represented in a great international museum like the British Museum.

That is true, as well, for our own art. A situation currently rumbling on is what we are told is the "danger" that one of Reynolds's greatest portraits, the Omai, might be sold and go abroad. That, in my view, would be a very good thing. British painting is barely understood or appreciated outside this country: foreign observers, if they haven't been to England, often have no idea of the sheer quality of British painting. It might actually be rather a good idea actively to encourage the overseas sales of a few masterpieces of this stature: we have plenty of Reynolds portraits, after all.

These situations have to be taken on a case-by-case basis, and there is no fundamental principle which applies equally. Moreover, when considering whether a work of art should be acquired and kept in this country, public institutions must carry out the extremely difficult exercise of trying to decide how much it is really worth.

Of course, a work of art is worth whatever the market says it is, and however much someone is prepared to pay for it. But that is not really good enough for a gallery considering whether to acquire it. Given the wild fluctuations in the value placed on works of art over time - consider the price of a Burne-Jones in the 1930s and in the 1890s, or indeed 1990s - a gallery must think whether the sum a work would fetch in the current market plausibly corresponds to its long-term worth. That is an almost impossible task, but it must be undertaken.

All these considerations come to the fore with the question of the Northumberland Raphael. The history of the painting is an extraordinary one, and a great deal of bad blood has arisen over it in the recent past. In short, the painting, a tiny Madonna, has been in the possession of the Dukes of Northumberland for as long as anyone can remember. Nobody paid any attention to it: it was always thought of as quite a pretty thing, picked up on some roistering Grand Tour in a bulk buy and hopefully labelled Raphael. It was probably the sort of thing knocked off by smart 19th-century Romans to flog to credulous milordi. Anyway, existing in this School-Of limbo, it had always been hung in passageways.

No one could expect that the tiny picture would, a few years ago, attract the gaze of Mr Nicholas Penny. Mr Penny is co-author of a remarkable study of Raphael, among other impressive works; he is an art historian of impeccable reputation and intellectual incisiveness; and, though he needs no more than that to justify his credentials in this case, he also carried behind him the authority of a senior position at the National Gallery itself.

Probably it is worth emphasising, however, the seriousness of this attribution, although I strongly believe that Mr Penny, who knows more than anyone about Raphael, would not come to this attribution lightly,or extravagantly. The discovery of an entirely unknown Madonna by Raphael is roughly comparable to the discovery of an unknown novel by Jane Austen, a lost tragedy by Shakespeare, or a new Beethoven quartet. It is almost incredible that centuries of reverence for Raphael have, until now, failed to turn up and identify this painting.

The National Gallery has a history of this sort of buccaneering raids on the Raphael territory; one brilliant success of recent decades had been to establish that their portrait of Pope Julius II was not, as had been thought, a studio copy, but directly from the master's hand. This, undoubtedly, was a triumph to top even that. The Northumberlands, understandably, were thrilled. From their point of view, it wasn't so much Mr Penny as the Man From the National Gallery who had spoken. They very decently agreed to lend the gallery, for an unspecified period, the painting, now formally titled the Madonna with Pinks and decisively attributed to Raphael, no question.

Perhaps, at this point, one might start to think that the National Gallery was the beneficiary here. After all, the Percys had graciously handed over the painting to the gawping multitude. But, in fact, it was the gallery and Dr Penny who had showered blessings on the Percys. They had benefited hugely from the gallery's imprimatur.

One of hundreds of long-ignored paintings turned out to be worth a fortune. Not only that, but one of the greatest public galleries in the world was proposing to hang the painting in the midst of its incomparable collection. What followed demonstrated, alas, that if the gallery thought that it was supplementing its remarkable series of Raphaels, the Percys thought of this as a chance to put the thing in the greatest shop window imaginable. And in the end, they made it very clear that, despite all the benefits they'd reaped from the National Gallery, they would have no compunction about selling the painting to the highest bidder.

In my view, the market value and authority of the painting had been so firmly established by the National Gallery that the Northumberlands had an honourable obligation, if they wanted to sell it, to see what the gallery was prepared to offer for it. In the circumstances, the National Gallery has behaved very well in choking back an understandable irritation on being told that a Californian collection had made a very substantial offer, reported as £35m, and producing an offer of its own, with the help of £11.5m from the Lottery.

The gallery must also raise £9m, and it depends on the Northumberlands accepting the payment partly in tax offsets. Though they could decide that they would rather have the cash, they must be prepared for us all to start saying what a pair of vulgarians they must be.

In this case, I think it is thrilling that this beautiful little Raphael is probably not going to leave the country. The National Gallery's Raphaels are a sensational sequence, and particularly good on Raphael's early years, to which this painting, dated just before his departure for Rome, solidly belongs.

The Madonna with Pinks belongs in the entrancing room that follows Raphael's style from its origins in Perugino to some of his greatest work; in California it would be an isolated jewel. Moreover, the gallery's investment in scholarship in this area, and the fact that it has become a centre for intellectual discussion means that many more people, from experts to school parties, will engage with this fine work.

We shouldn't always be chauvinistic and possessive about our treasures; in this case, there is something worth fighting for. It has not been an entirely happy experience, but with some luck, the story can still have a happy ending.