The ornate Bute epergne, made by Thomas Heming, was designed by William Kent. Photograph: Courtesy of the Sotheby's Picture Library  There's an ingrained idea that Georgian England was all about dignity and restraint: grey-beige country houses, and well-proportioned city terraces which, as Ludwig Wittgenstein would say about their Dublin equivalents, have the good taste to know that they have nothing very important to say. It is an idea challenged as you enter the V&A's new show, by a slab of multi-coloured marble supported on a gilded fusion of beasts and scrolls.  The object is a console table, but its purpose was to make you notice the marble, which was expensive. It was designed by William Kent, painter, decorator, designer of furniture, objects, stage sets and costumes, book illustrator, and architect of buildings and landscapes, whose clients included the holders of wealth inflated by the South Sea Bubble. As well as wielding gilt, and more gilt, Kent would line enfilades of rooms with ceaseless red damask. He would decorate domestic ceilings with preposterous mythological scenes. He designed writhing silver chandeliers, and gold epergnes formed like indestructible confectionery, off which to take your dessert.  It is not difficult to draw parallels with the bubble architecture of the last decade, ostentatious and excessive, but near to the console table is a more chaste exhibit. This is a copy of the Letter Concerning Design of 1712 by the philosopher and politician the third Earl of Shaftesbury, which called for a new English aesthetic to suit a rising and confident nation, and the freedoms of its aristocracy. (Albeit one, paradoxically, with a strong Italian flavour.) It is an early example of the use of "design" in its modern sense, and as something linked to national pride, ideas which in the 19th century would be the foundation of the V&A itself.  Kent, as shown here, rode both horses. He was a charming social operator who, as the co-curator Julius Bryant says, was "overweight and liked cherry brandy", and would "move in with you", while he designed your camp-kitsch interiors. He also designed Horseguards Parade and the Treasury, monuments to the power of army and money in Georgian England, and unrealised projects for new Houses of Parliament and a royal palace in Richmond. He led a project to make Westminster Abbey into a national pantheon of great Britons, and designed monuments to Newton and Shakespeare. The latter, showing him leaning musingly on a pile of books, became one of the stock, much-reproduced images of the playwright.  With his patron, collaborator and possible lover Lord Burlington he created Chiswick Villa and its gardens, a manifesto of the new design that Shaftesbury wanted, that did indeed aim at the dignity, restraint etc that myth ascribes to Georgian architecture. At Rousham, Stowe and elsewhere he led the creation of a new type of landscape garden, which aimed to bring out the best in nature rather than to dominate it, and was one of 18th-century England's greatest gifts to the visual culture of the world. His most substantial single work was Holkham Hall, a valiant attempt to evoke the Palladian villas of the Veneto in windy, marshy Norfolk.  At the root of Kent's social and artistic career was the Grand Tour of Italy. Kent was himself a humbly born Yorkshireman, but he spent several years in Italy, mentoring the young nobility who went there to expand their horizons. He created an aura around himself as "Kentino" or "Raphael Secundus", an English reincarnation of great Renaissance artists. As Bryant puts it: "He played the Italian card for the rest of his life." He reminded patrons that "I'm the guy that you had that great time with when you were a teenager" during the drear decades of their adult after-life, spent draining East Anglian fens so that they could build a memory of their sunlit youth.  It's likely that Kent preferred gusto to taste. He seems to have been happier making golden patisserie, or framing views of well-formed naked Apollos in the gardens of Rousham, than composing the dutiful symmetries of government buildings. He liked theatre and illusion, and created temporary ceremonial structures for the royal family. He liked stories and fables and painted some truly awful pictures that were supposed to connect the Hanoverians to the heroic Henry V. You don't want to look too closely at many of his drawings, which can be scratchy and uneven, or at much of the painting and sculpture in his interiors and gardens, which are conventional-going-on-humdrum. His buildings can be pedestrian and oddly scaled. But to worry too much about these things is to miss the point of Kent. His desire seems to have been to create a series of spaces of society, illusion and delight. Where some architects treat stone as a more serious material than damask, or gilt, or foliage, or trompe l'oeil, Kent gave them the same worth as one other, all sensual surfaces, and all means to the same theatrical end. Buildings were less ends in themselves than frames that allowed everything else to happen.  Such is the version that the V&A show communicates. It takes you on a winding path, cut through with vistas like Kent's gardens, lit with the warm hues of his interiors. The architecture, when you come to it, is almost incidental. Birdsong plays in the section on gardens, and Handel's Water Music close to material on the beautiful/absurd barge that Kent designed for Frederick, Prince of Wales. In most exhibitions this ear-fodder would be infuriating, redolent as it is of pretentious 1980s restaurants, but in the not-too-solemn spirit of Kent it makes sense.  Kent was an atrocious painter, a so-so architect, a good designer, a great landscape architect and a socialite of genius. He was mostly loved, and had an ability to work for all sides of hostile factions, but not universally. Hogarth, rightly angered that Kent's social skills won him commissions to which his artistic skills were not equal, called him not Kentino but KNT, which was meant to be as rude as it sounds.  For all these reasons Kent is a significant figure in British design, and the exhibition is an essential part of what the V&A should be doing. But it is a struggle, apparently, to find the space and money (a million pounds or so) to put on shows like this. The Kent project, which includes an imposing 600-page book, was only possible with the help of the Bard Graduate Centre in New York whose director Susan Weber co-curated with Julius Bryant. For which thanks.
The V&A celebrates the life of the flamboyant figure who brought opulence and flair to a 'beige' Georgian Britain, writes Rowan Moore