Philip Hensher: British art is as exciting and heroic as any in Europe

'Many English painters attempt philosophy, only to find that cheerfulness keeps breaking in'

The opening of the rebuilt and rehung Tate Britain is a cultural event to match, and perhaps even surpass, the opening of Tate Modern. After years in which the incomparable collection was squeezed into half a museum, and then subjected to the indignity of a "thematic" hang which, in many people's view, made it quite impossible to look seriously at much of the art, it is finally displayed in a way that demonstrates the strength, beauty and continuity of the holdings, and, indeed, of British art itself.

I was extremely rude about the thematic hang at the time, and, if it's not just a great relief but a great pleasure to be able to sing the praises of this superb refurbishment, that's because of the unique nature of Tate Britain. Tate Modern is a fine museum of international contemporary art but it is competing in a very crowded market. There are many museums of 20th century art across the world, and several that are as good or even superior in quality to Tate Modern. Tate Britain, on the other hand, is unique. There is no museum in the world that has devoted itself to chronicling British art so consistently, and none that has holdings to rival the Tate in quality – the Paul Mellon in New Haven runs a distant second.

That's why the thematic hang, which abandoned any attempt to tell the story of British art, seemed so damaging. If the Tate lost interest in explaining the slow, organic growth of culture from the Tudor court painters through Lely, Hogarth, Constable, Ruskin, and Bacon right up to the present day, then no one else in the world would be doing the same job. If your first encounter with British art occurred at the Tate until recently, you would have gone away baffled, and confirmed in your sense that British art was not a daring or ambitious affair.

All that has been changed at a stroke, and the visitor enters a room of incomparable Tudor art, beginning with a loaned Holbein of the Queen's, with a sense of deep, reassured rightness. What interests me is that this relatively neutral, historical hang frees the visitor to pursue his own thoughts and make his own connections through the long development. What makes British art specifically British? What qualities in such different artists as Burne-Jones, Blake, Hogarth and Bacon unite them so that they each look unmistakably British?

It's difficult to define national characteristics in art, and British art is as various as anything, but there are a few deep-rooted flavours that surface over and over again. There's a practical, come-off-it air about it. Like Dr Johnson's friend Edwards, many English painters attempt philosophy, only to find that cheerfulness keeps breaking in. In Hogarth, the most elevated and debunking moods jostle for supremacy – George II, famously, couldn't catch the tone of The March To Finchley. Stubbs produced the greatest images of the English Enlightenment mostly out of the everyday, and Wright explored the sublime not just in paintings of erupting volcanoes, but in images of iron foundries and scientific experiments.

The extravagant and fanciful is there in bucketloads, but there is always something down to earth pinning it down, even in Turner's airy dreams. Gainsborough's sitters remain real people; Reynolds's sitters, enacting elevated mythological roles, are not gods and goddesses, but well-fed gentry at play. The practical side is only half of it, though; from Blake through Burne-Jones to Cecil Collins there is a visionary, inward vein in English painting that often defies description. English painters can be exuberant and grand, but the tenderest and most characteristic imaginations are the most introverted and secretive.

There is, too, a recurrent English palette, which seems to value restraint in two quite different ways. When the colours are pure and bold, the clarity and purity of the design seem to impose some kind of inner restraint – a manner that goes from Holbein to Patrick Caulfield without a break. Elsewhere the British painter is drawn, over and over, to silvery tones and tiny distinctions between tinted shades of grey, in Allen Ramsay, Burne-Jones or David Jones. Everything, it seems, has been seen through rain.

What the British tradition is particularly rich in, however, is painters who develop a particular, stylized manner of rendering reality and explore the artifice with constant delight. Gainsborough's brushstrokes, Francis Towne's airy fields of colour, Samuel Palmer's bubbling textures, Edward Burra or Francis Bacon's calligraphic styles – these, somehow, are the most British of painters in their devotion to a particular, narrow manner, and demonstrate that highly evolved mannerism is no barrier to the achievement of greatness.

Tate Britain is as rich and as various as any good museum of a great national art. Anything you propose about the specifically British quality of British art can, in a moment, be disproved by a counter-example. But that's the point. British art, so long undervalued, is as exciting and as heroic as any national tradition in Europe. It is thrilling that, at last, we have a museum which so incontrovertibly demonstrates that fact.

hensherp@dircon.co.uk