Nowadays, a Norman Foster building in Hong Kong looks just like a Norman Foster building in Canary Wharf - neither British nor Chinese, just nationless steel and glass in both places. However big the modern Chinese economic boom, it has absolutely no stylistic effect on our buildings over here. We congratulate ourselves for being tremendously multicultural these days. Not when it comes to new architecture, we're not. We were much more open to in fluences from abroad two centuries ago, taking styles from all round the world and modifying them to suit our cool home climate.
Baronial and colonial in its style;
Gables and dormer-windows everywhere,
And stacks of chimneys rising high in air . . .
"Lady Wentworth" (1862)
Longfellow was writing about the house in Portsmouth, New Hampshire, that had belonged to the British governor Sir Benning Wentworth. In 1760, in a great scandal of the time, 64-year-old Wentworth married his 23-year-old housekeeper, Martha Hilton. When British grandees of Sir Benning's ilk returned home, with or without a young bride, they brought back with them that baronial and colonial style and used it to erect country houses and villas across Britain.
They also unwittingly started a trickle-down effect: the exotic styles spread from these grand, one-off projects into terraced houses, municipal baths, hotels and theatres throughout the country. While the empire boomed, as it did between the 17th and early 20th centuries, echoes were heard back home on British building sites.
The influence of the Renaissance and the Greek Revival on our classical buildings is obvious enough. What isn't celebrated is the tremendous absorption of more tropical influences into Brit ish architecture - Indian verandahs in the Home Counties and Indian bungalows by the seaside, Chinese interiors at Brighton, Moghul temples in Gloucestershire and Egyptian sphinxes opposite Tony Blair's old terraced house in Islington. Once these foreign styles hit our shores, they went through a blending process, producing a peculiarly British version of the original. This exoticism has become so domesticated that we have grown blind to it - today, you can pass a structure such as Alexander "Greek" Thomson's 1859 church in St Vincent Street, Glasgow, and hardly notice that it's not just Greek, it's an internationally unique confection of a Greek portico on an Egyptian foundation, beneath a tower based on a Hindu temple with Assyrian details.
It is not surprising that India, the empire's cash machine, had a particularly seismic effect on the decor of returning colonial servants. The first great house influenced by Indian or "Hindoo" - or, strictly speaking, Indo-Saracenic - style was Sezincote (1805-17), in Gloucestershire, built for Sir Charles Cockerell by his brother Samuel Pepys Cockerell, surveyor to the East India Company. (The family had deep colonial roots: another brother, Colonel John Cockerell, had returned from Bengal in 1795 to buy the estate.)
Sezincote is a light and airy skit of a house, but its borrowed details are learned and complicated. Its jigger-jagger arches, minarets, peacock-tail windows, jali-work railings and daringly deep cornices were Moghul outside, Greek Revival within. John Betjeman stayed there in the 1920s with a friend - John Dugdale, whose father owned the house - and wrote about it in Summoned by Bells (1960), his blank-verse autobiography:
Chajjahs and chattris made of amber stone . . .
Stately and strange it stood, the Nabob’s house,
Indian without and coolest Greek within.
Chattris (or chhatris) are the slim minarets on the corners of the building and chajjahs (or chhajjas) projecting cornices with their deep brackets. Like the dome, these were Muslim devices. Above the front door an iwan, or arch, reaches right up to the roof, as in the mosques of Bokhara and Samarkand, the ancient Moghul homeland. This powerful cocktail of stone and glass resonated in the dome of the Brighton Pavilion, which John Nash began building ten years after the first work on Sezincote. The pavilion jumped all over the place for inspiration, from Hindoo domes, through dragons snaking round bulging chandeliers and glaring at fake-bamboo furniture, to luridly coloured Chinese vases.
In the most widespread example of that trickle-down effect, the eastern look caught on in 19th-century terraced houses across Britain. Front parlours bulged with decorative fire-irons, frosted glass, china knick-knacks, bamboo chairs and pot plants. In 1798, Brighton's Royal Crescent presented the first notable British verandah, an idea brought back from India by colonial nabobs who thought it beneficial in the moderate heat of the northern European summer. The word verandah comes from the Hindi varanda, itself originally Spanish or Portuguese, meaning railing, balustrade or balcony. Bungalows also took their name from Hindi, from bangla, meaning Bengali and signifying, in this context, a house in the Bengal style - that is, a one-storey, thatched dwelling with a verandah. In a pattern that became familiar, the English language adopted the foreign word before the English landscape borrowed its physical incarnation.
In this way, as early as 1676, the splendidly named Streynsham Master, a colonial civil servant working for the India Office, wrote in his diary, "It was thought fitt to sett up Bungales or Hovells for all such English in the Company's service" - but the first British bungalows did not appear for another couple of centuries.
Since the dawn of time, shortage of funds had dictated that most humble houses in Britain be one-storey. It was only in the late 19th century that those who could afford two or more floors began to go for one-storey structures as a positive style choice.
These first bungalows were built at Westgate-on-Sea and Birchington, both on the Kent coast, in 1869. The seaside connection gave them a healthy holiday air. The artist Dante Gabriel Rossetti moved to a bungalow in Birchington to recover from illness. He died there in 1882.
In the 18th century, not only was architecture in different countries more idiosyncratic, but there was also a much more vigorous exchange of highly individual motifs between countries, particularly China and Britain. The earliest Chinese buildings in Britain were erected at Wroxton, Oxfordshire, in 1753, but there had been earlier glimpses: at Stonyhurst, the Lancashire school, there is even a Chinaman's face on the main keystone of the 1699 building.
When it came to textiles and porcelain, the Chinese fashion had been around since the late 17th century. The Treatise of Japanning and Varnishing (1688) by John Stalker and George Parker was the first pattern book for British craftsmen copying Chinese motifs in lacquer, silver, ceramic and textiles. In Hogarth's Tête à Tête, from his series Marriage à-la-Mode (1743), you can see, behind the dissipated couple, a Chinese fire screen and clock and several smiling Pu-tai figures, take-offs of the Chinese god of happiness.
Building caught on to the trend half a century after textiles, partly in reaction to the ever-tightening straitjacket of Palladianism: the domination of practically all major construction commissions in the first half of the 18th century by the classical style. In 1750 the writer Horace Walpole wrote to his friend Sir Horace Mann in Florence: "I am sure whenever you come to England, you will be pleased with the liberty of taste into which we are struck." He remarked of the new Chinese buildings that they brought "a whimsical air of novelty that is very pleasing".
Just as Chinese food in Chinatown bears little relation to Chinese food in China, early Chinese buildings were hardly authentic, borrowing and exaggerating the most comical original features. An early home-grown Chinese takeaway was Sir William Chambers's pagoda at Kew, completed in 1762. At 163 feet, it was the tallest Chinese structure in Europe. Purists, however, object to it - traditional Chinese towers had an odd number of floors; the Kew pagoda has ten.
British architects were tremendously quick to adapt to the new styles. Many of those classical Palladian houses very soon developed their own rooms packed with chinoiserie. In Brideshead Revisited, the Chinese drawing room at Brides head Castle (a house built in the 1670s, Evelyn Waugh wrote) is a 1750s addition, "adazzle with gilt pagodas and nodding mandarins, painted paper and Chippendale fretwork". It is in this "splendid, uninhabitable museum" that Lord Marchmain chooses to die.
The peculiarly British openness to new fashions meshed happily with the colonial hunger for new possessions. Thus, Egyptian motifs became popular after Nelson won the Battle of the Nile against Napoleon's navy in 1798.
More than ten years later, in Maria Edgeworth's novel The Absentee (1812), Egyptian themes were still all the rage. An early professional interior decorator, Mr Soho, advises Lady Clonbrony, who is married to a dreary Irish peer, to deck out her ballroom in the prevailing fashion. "If your la'ship prefers it, you can have the Egyptian hieroglyphic paper," he says, "with the ibis border to match! The only objection is, one sees it everywhere - quite antediluvian - gone to the hotels even."
The Egyptian style lasted long into the 19th century, accounting for one of Britain's strangest terraces. On Richmond Avenue in Islington, north London, the handsome villas are guarded by a quirky set of sphinxes and obelisks. The sphinxes stare across the road at Tony Blair's old home in Richmond Crescent - the one that Cherie Blair is so cross at having sold for £615,000 in 1997. (Even after the recent fall in house prices, it is still worth £1.8m.) So great was Nelson's fame that these lovely little sphinxes and obelisks were inscribed with the word "Nile" in 1841, 43 years after the battle, by Joseph Kay, surveyor for Islington's Thornhill Estate.
Such accumulation of vastly different styles over many generations is not unique to British buildings in particular, but I think the artless, mishmash, make-do-and-mend attitude to this accumulation is. How daring and original to whack an Egyptian sphinx on to the front of a house which, like most British terraces, has Italian Renaissance origins. The height of the windows in our terraces, the space between them, and the layout of the rooms inside, are all drawn from northern Italian palazzi built by Andrea Palladio in the middle of the 16th century.
It is from such daring, small-scale, on-the-hoof improvisation, mixed over the years with a pleasing decay, that the magic of Britain's architectural past grows. Vita Sackville-West once said that all truly British buildings, like her beloved Knole in Kent, were pre-Renaissance, dating from before the influence of Palladio and his fellow clas sicists. You can see her point; so many British buildings from the Renaissance onwards had a large dose of foreignness poured into them. And yet it is this same, strange openness to foreignness - the waves of different styles all slapped on top of and mixed up with each other - that makes them unique, and British, too.
Harry Mount's "A Lust for Window Sills - a Lover's Guide to British Buildings From Portcullis to Pebble-dash" is published by Little, Brown (£12.99)