England's King George III thought he was a pane of glass that could shatter under stress. In 1811, his insanity obliged him to retire from royal duties, in effect ending 51 years of misrule, during which he lost a colony called America.

His son became Prince Regent - but he was no rock, either. His life revolved around hard drinking, womanising and gambling. He also blew money on lavish building projects, commissioning his favourite architect John Nash to design Regent's Park and transform the aristocratic pile known as Buckingham House into Buckingham Palace. Alas, the Prince Regent died in 1830, at the age of 68, before the palace was finished.

But he did live to make the most of another Nash triumph, set in the bawdy southern resort of Brighton, or Brighthelmstone, as it was then known. Built on the site of a neo-classical villa that had once been a farmhouse, the Royal Pavilion was completed in 1822, by which time George III was dead and his son crowned king. When George IV set eyes on the finished product, he supposedly wept with joy.

A reflection of his extravagance, his legacy sprawls on the edge of Brighton town centre, flanked by a park on one side and boutique-shop backstreets on another. On the outside, with its onion domes and minarets, the pavilion resembles the Taj Mahal. Inside, beyond the octagonal hallway, the Chinese-style decor challenges the visitor's assumptions about good taste. Dragons are everywhere: the most striking example is a silvery beast that hangs from the ceiling of the Banqueting Hall, gripping a chandelier in its claws.

In the Music Room, where the king's own band beguiled guests with selections from Handel and Italian opera, giant porcelain pagodas gleam under lotus-shaped gas lights. Throughout the interior, the dominant colours are those oriental symbols of fortune and wealth, red and gold. Opulence permeates every room. Even the kitchen is over the top, its ceiling supported by four cast iron columns carved to resemble palm trees.

The new pavilion drew celebrities such as the composer Rossini and the poet Lord Byron, who in 1821 wrote a verse drama, Sardanapalus, about the Assyrian king's pleasure palace.

The pile did have its critics. The Georgian writer William Cobbett compared it to a jumble of turnips and tulips. George IV's niece, later Queen Victoria, dismissed it as 'strange' and 'odd'. In the late 1840s, she whisked most of the furnishings, carvings, fireplaces and even the wallpaper to Buckingham Palace and sold the shell to the council.

Restoration, which continues to this day, began. Meanwhile, the pavilion served several purposes, hosting exhibitions and business events, as well as acting as a hospital for Indian soldiers wounded in the first world war. Thanks partly to funds from Queen Elizabeth II, the pavilion is again in fine fettle.

Adding to the fantastic allure, the pavilion even has a secret tunnel or two. Better yet, the ghost of playboy king George IV supposedly roams the underground passages, doubtless still looking for a good time.

The Royal Pavilion, Brighton, Sussex, England BN1 1EE. Tel: [44] 1273 290 900. Go to www.royalpavilion.org.uk