Even on the ten thousandth occasion, a walk along Whitehall ought to remind one that history is now and England. At one end, the Houses of Parliament. After centuries of conflict, bloodshed and constitutional development, the proud and angry dust of the embattled dead is harmonised into grandeur and beauty. Just opposite, with an even older provenance, is Westminster Abbey, the parish church of the British Empire, resting-place for so many of those mighty dead. Around the buildings, there are the statues, including the three Lion-hearts: Richard Coeur-de- Lion, Cromwell and Churchill.

Then Whitehall itself, taking its noble course past the bureaucratic palaces from which the Empire used to be governed, monuments to national selfconfidence and national achievement. One’s eye is caught by Nelson, but also by another tragic figure, Charles I, hard by his own Whitehall. If the Thames is liquid history, Whitehall is history in brick and stone. There is no better place for a history lesson. Was Charles I merely the author of his own misfortune? Was Cromwell a great man, and what about Jan Smuts? Within a few hundred yards, there is enough material for a Methuselah’s life-span of hard thinking.

There is also the material for a lifetime of rage and despair. In today’s Whitehall, history and England are equally defaced. At one end, in Parliament Square, a tinker encampment has taken root. A leftist rabble is determined to offend every decent eye and pour scorn on every decent value. The nerveless authorities seem powerless to prevent them. At the other, in Trafalgar Square, there are usually preparations for the next pop concert, while the fourth plinth in the paladins’ enclosure is occupied by a piece of junk that looks as if it had been liberated from Steptoe and Son’s scrap-yard.

The systematic abuse of Trafalgar Square began under Ken Livingstone, who at least had a goal. He wanted to turn Whitehall into the Avenue of Cultural Humiliation. But nothing has changed under Mayor Boris. Malcontents have alleged that the Mayor is a shallow, frivolous fellow. Those who might wish to defend his reputation ought to avert their gaze from Trafalgar Square (to be fair, he has not yet handed over the fourth plinth to Lady Hamilton). No serious country would allow its monuments and sacred places to be trashed in this fashion. So there is only one conclusion to be drawn: that we modern British are no longer a serious people. We have degenerated into a race of cultural and moral pygmies, scuttling in the shadows of our forbears’ greatness, as indifferent to the glories as are the rats which scuttle below the streets.

Thus, passing Nelson, concluding that posterity was unworthy of his sacrifice, I arrived at the National Gallery. In the basement of the Sainsbury Wing, I found, if not quite the dearest freshness deep down things, at least some reason for refusing to abandon all hope. The National Gallery dates from an era when we had not lost our sense of the fitness of things; when it seemed natural to endow London with the finest works which artists had created. Within these walls it still does, and in its ceaseless pursuit of excellence the Gallery has harmonised connoisseurship and science.

There is a fascinating exhibition: ‘Close Examination: Fakes, Mistakes and Discoveries’, dealing with the problems involved in attributing paintings, and the use of scientific techniques to reinforce scholarship. X-rays, ultraviolet light, infrared radiation, electron microscopes: all of them enable us to look below the surface of the painting. They can lay bare the artist’s preliminary draughtsmanship; they can also expose the forger’s deceits. Although a tremendous amount of work went into this exhibition, the organisers never lose sight of the psychology of the individual. In 1937, the Gallery’s young director, Kenneth Clark – later Lord Clark, of Civilisation fame – was offered four early sixteenth century Venetian paintings. He thought that they might be by Giorgione and would therefore fill a major gap in the Gallery’s collection.

The trustees pushed him on the attribution. After all, the price was £14,000, a lot for the 1930s. One can also imagine the Temptation of Clark: to go down in history as the Director who acquired the Giorgiones. So he went firm, and rapidly regretted it. The scholarly consensus was heavily against him, and one can see why. The paintings have charm, but lack greatness. The Giorgione catalogue raisonné has always been complicated. At one time or another, most of the paintings now regarded as his were assigned to others. But there seems no reason to dispute the downgrading of the Clark foursome, to a minor contemporary, Andrea Previtali.

The controversy had consequences. When the National Gallery was next offered a Giorgione, in the late 1950s, there were over three years of agonisings before the decision to purchase. That was a splendidly right outcome, as the current exhibition demonstrates. But one question remains unanswered. The painting is known as Il Tramonto (The Sunset). This is faute de mieux, and more faute than mieux. As with Giorgione’s greater work, La Tempesta, no one knows how it should be interpreted. Is it a landscape with figures, is there a Biblical or ecclesiastical theme, or is it simply a landscape capriccio? The Gallery’s scientists have proved that it is a Giorgione. There is still scope for genius in explaining the theme. This exhibition might provide a further outlet for genius. In the nineteenth century, Velazquez’s Dead Soldier had a considerable influence on other artists, inter alia inspiring Manet’s Dead Toreador. But there is now widespread agreement that, fine as it is, the Dead Soldier is not by Velazquez. So who did paint it? As there is no obvious answer, inspiration is required.

Or is it? Given the work’s many Velazquez-like qualities, it is tempting to draw on the late Frank Johnson’s solution to the ‘who wrote Shakespeare?’ debate. ‘I have come up with the answer,’ Frank would say, ‘It was not William Shakespeare. It was someone else with the same name.’ The forensic scientists believe that the painter was Italian. Their certainty is impressive. Even so, I am not entirely convinced.

‘Close examination’ does provide some reassurance. The authenticity of Uccello’s delightful St. George and the Dragon had been questioned. Are no certainties immune, no beauties safe from violation? In this case, thankfully, they are. The scientists’ techniques have vindicated the eyes’ delight.

There are disappointments. It transpires that the Dürer portrait of his father, sent from Nuremberg as a gift to Charles I, is only a copy, though a good one. As always, its juxtaposition with the Dürer self-portrait is piquant. The reserved, melancholy father looks as if he has been chastened by life. The jeunesse dorée son looks as if he regards life as a bowl of cherries. Dürer the Younger would have been a cavalier: the Elder, a roundhead. A fusion of science and connoisseurship has dealt with another difficulty. Although Verrocchio is better known as a sculptor, he was a painter of the first rank, and also a businessman. He ran an efficient studio, in which his pupils’ efforts were employed to maximise revenue. This has made it hard to work out what he himself painted, but in one case, the National Gallery has succeeded. We now know which parts of The Virgin and Child with Two Angels are by Verrocchio. We also know that they are paintwork of the highest order, comparable with his superb drawing of a female head in the recent exhibition in the British Museum. This should help to solve some of the other problems of attribution, which Verrocchio himself created.

In a small space, the exhibition takes us from the sublime to the cheeky. There is one amusing early twentieth century fake Renaissance portrait which deceived the National Gallery in 1923. Then there is a pseudo-Guardi so entirely lacking in Guardi-esque qualities that it is hard to see how it could have fooled anyone who did not require a white stick. The scientific restorers have also rescued important paintings from neglect, and from the ‘improvements’ made by earlier generations in order to enhance a painting’s value. A Bellini and a Botticelli can now be properly appreciated, though an early de Hooch may be beyond full restoration.

The exhibition ends on a note of triumph. In 1991, the current Director of the Gallery, Nicholas Penny, paid a visit to Alnwick Castle. Neglected among the ducal treasures, he saw a copy of a Raphael and instantly realised that this was no copy. Some doubted the attribution because the painting was in a Flemish style. Others reminded us that the Flemish idiom was popular in Italy during Raphael’s early years. Nick Penny had no doubts. He saw a perfectlyachieved masterpiece, which has become one of the jewels of the National Gallery. Kenneth Clark was always subject to embarrassment over the Giorgione. Dr. Penny will receive enduring praise for the Madonna of the Pinks.

The organisers of ‘Close Examination’ are equally praiseworthy. Betsy Wieseman and her team should remind us just how much a great Gallery depends on underpaid research and learning. The exhibition should not be missed and Dr. Wieseman’s catalogue is to be savoured, for it is a harmony of science and art. In the piazza outside the National Gallery, the yahoos gibber and caper, their bestial cachinnation often intruding on the Gallery itself. Within, thank God, dumbing down hath no dominion. The resources of civilisation are not yet exhausted.

‘Close Examination: Fakes, Mistakes & Discoveries’ is at the National Gallery until 12 September 2010
A Closer Look: Deceptions & Discoveries by Marjorie E. Wieseman (National Gallery Company) £7.99