No need for a wedding list...

Prince Billah's marriage to his cousin tomorrow will be one of the most extravagant events ever seen in oil-rich Brunei. Jan McGirk makes a toast (non-alcoholic, of course) to the happy couple

Palace lackeys are polishing golden chains and ruby-encrusted daggers in Brunei this week. The remote petro-fiefdom on the northern coast of Borneo is going overboard (which is saying something for this gilt-laden country) for what promises to be the most lavish royal wedding of the decade. Its ruler, Sultan Hassanal Bolkiah of Brunei, has been hosting street dances and candle-light processions since 26 August as part of a month-long jolly to celebrate the marriage of his eldest son. The celebrations reach their zenith tomorrow; the monarch has declared it a national day of rejoicing.

Palace lackeys are polishing golden chains and ruby-encrusted daggers in Brunei this week. The remote petro-fiefdom on the northern coast of Borneo is going overboard (which is saying something for this gilt-laden country) for what promises to be the most lavish royal wedding of the decade. Its ruler, Sultan Hassanal Bolkiah of Brunei, has been hosting street dances and candle-light processions since 26 August as part of a month-long jolly to celebrate the marriage of his eldest son. The celebrations reach their zenith tomorrow; the monarch has declared it a national day of rejoicing.

Even though the Sultan's fabled personal fortune of £45bn is diminished after years of family splurging (he now ranks down at No 21 with £7.5bn in assets instead of topping the list of the world's wealthiest men), he is not apt to scrimp on such momentous occasions. And, after the price of crude oil nudged record highs this summer, a few gestures of opulence will be expected by the dignitaries and well-heeled wedding guests jetting in from the Arabian Gulf and the Pacific Rim. After all, the Sultan famously flew Michael Jackson over in 1996 to serenade him thrice on his 50th birthday.

But clearly, nothing less than the extraordinary will do to celebrate the first marriage of the first-born son from the Sultan's first wife, Queen Saleha. Crown Prince Pg Muda Hj Al-Muhtadee Billah, 30, weds the 17-year-old Dayangku Sarah binti Pengiran Salleh Ab Rahaman tomorrow. Formal portraits of the betrothed couple are already hoisted over vast banks of red, yellow and blue flowers lining the thoroughfares across the spruced-up capital, Bandar Seri Begawan. Officially, the wedding banquet will be a teetotal affair.

Gossips who track the world's most eligible bluebloods note that Brunei's Crown Prince has only recently become attached to young Sarah, who is a distant royal relative. A Bruneian student commented in the anonymity of an internet chatroom: "His Highness had to split up with his ex-girlfriend. She was viewed as too common and is out of the picture. She left the country in a huff." Also in a huff was this contributor, who added: "People say that the Prince took his pick from a roomful of virgins at his 30th birthday party in February. But nobody in my crowd was invited."

Even if this wedding happens to be a family affair, there will be scant risk of any potential heirs to the throne suffering from inbreeding. Brunei's monarchy has been compared to the American television sitcom The Beverly Hillbillies because of the preponderance of marriage between "kissing cousins" and their rather unsophisticated approach to their vast oil wealth. But in this case, a fresh European bloodline comes through Sarah's Swiss mother, the former Suzanne Aeby. While working in London as an au pair in the Eighties, she was swept off her feet by a minor Bruneian royal, Yang Mulia Pengiran Salleh binti Ab Rahaman. Sarah and her elder brothers Irwan and Adrian have since lived a comparatively sheltered existence in Brunei.

The doleful Crown Princess Masako of Japan, whose court physicians advised against her attending the royal wedding because it would interrupt her treatment for stress, made headlines when she sent her regrets last week. Her situation may be seen as a cautionary tale for the newest princess bride in Asia; palace life has proven utterly claustrophobic for Princess Masako. A highly-educated, cosmopolitan woman who grew up abroad, she has faced enormous pressure to produce at least one male heir for the Chrysanthemum Throne. But after 11 years of marriage and one miscarriage, the Japanese royals have one daughter, Princess Aiko, aged three. Bored, lonely and increasingly unhappy, Princess Masako recently took refuge in her parents' home.

Brunei's princess-to-be appears to be considerably more robust. Sarah, not yet enrolled in university, likes to scramble up cliffsides and scuba dive, and enjoys sailing and abseiling. "She is known for her grace and diligence," says the blurb on the government's wedding website. She also likes sporting pastimes that conspicuously burn up the kingdom's main export, petrol; Sarah's passion is navigating on ambitious four-wheel-drive vehicle expeditions that cross international borders.

The bridegroom is rather more indoorsy. Crown Prince Billah graduated from Oxford, after reading Islamic studies at Magdalen under a bogus commoner's name, Omar Hassan, in 1997. His investiture took place the following year, but he is still keen on the less-than-regal sports of badminton and snooker, rather than the polo that excites his Sandhurst-educated father. He follows football avidly and plays in goal on the national team when the whim takes him.

Long before "bling" became a byword for street cred, the Brunei royals set the standard for big spending on tacky baubles. The Sultan, known as The Big One - despite his small stature - and his younger brother Jefri were heavily into retail therapy, blowing huge sums on hotels, jumbo jets, yachts, race cars and bizarre erotic jewellery. Where they went, servants, confidants, playmates and camp followers tagged along. "Even the entourages have entourages," sighed one harassed source.

Brunei, roughly the size of Norfolk, perches atop hefty reserves of oil and natural gas. Petro-dollars still keep the royal treasury topped up and maintain per-capita annual income at $25,000 (£14,000), and no one pays income tax. The Sultan has no urgent plans to introduce democracy, although he has convened parliament for the first time in 20 years. But the popular ruler dispenses free healthcare, education and housing for his 230,000 subjects.

A further dent in the coffers came when Prince Jefri's holding company Amedeo collapsed in 1999 - a result of his involvement with the Asprey & Garrard jewellery company (onlookers quipped that he spent so much money there, he might as well buy it). The mess even threatened to bring down BIA, the Brunei investment agency. These losses mortified the Sultan, who had offered loans to keep afloat struggling neighbours Thailand and Indonesia, only to discover that Brunei could ill afford them.

Prince Jefri was restricted to a $300,000 monthly allowance while he dealt with a civil action brought against him by the Sultan, and he agreed to hand back all assets he had acquired during his 13 years as the finance minister. The family feuding has cooled, but not abated, while the Prince flits between residences in London, Paris and the United States. He has complained that conservatives in society set him up for a fall.

Brunei Shell Petroleum has just presented the Sultan with half a million dollars to top up the wedding fireworks display - an odd whiff of corporate sponsorship for a royal marriage feast - and at least another $250,000 has been spent on landscaping the capital. Estimates of spending on wedding finery or refreshments - not to mention the value of heirloom jewellery - are extremely difficult to winkle out of courtiers in a kingdom that is hypersensitive about financial data or suggestions of creative accounting. Ever since the Sultan's debt-ridden brother was forced by creditors to auction off impulse buys worth £3bn, from gold toilet-brush holders to attack helicopter flight-simulators, in an embarrassingly public jumble sale in London three years ago, the royal family has eschewed excess. But belt-tightening is relative.

One of the biggest quandaries for the newlyweds may be selecting which family sedan will make the most impressive going-away car. Earlier this year, the Sultan went right to the source, the Rolls-Royce factory in Chichester, to pick up a dozen Phantoms for a cool £5m. All have bullet-proof windscreens and armour-plated bodywork. But, with the kingdom's recent emphasis on traditional Islamic rites and royal heraldry, the bride and groom might end up riding in a golden palanquin, hefted along by 40 strong men. The Sultan was carried through the streets in one to celebrate his silver jubilee.

The royal lifestyle in Brunei remains impossibly extravagant. The main family home is an art deco schlock palace, whose style is reminiscent of Liberace or Elvis Presley. Bigger than Versailles, it boasts 1,788 rooms, 200 bathrooms, more than 500 chandeliers, at least 2,000 telephones and a monstrous banquet hall where 4,000 can be seated for dinner. Pride of place is given to a Renoir painting, bought for $70m in the 1980s. When told by his friends that this dream house might be a bit over the top, the Sultan simply built a less ostentatious one, where he entertains those with more minimal tastes.

Like all gatherings, there will be an unavoidable cringe factor at the Brunei royal wedding. In order to get along with the in-laws, Princess Sarah will soon learn that the names of certain relations are best not mentioned. The Sultan's ex-wife, for example, is Mariam Bell, a former flight-attendant whom he divorced last year after 21 years of marriage. Already stripped of her title, she is not expected to attend her stepson's big day, although her four royal offspring may take part in the ceremony. Her settlement of $3.5bn presumably put a big dent in the wedding budget.

Even more conspicuous by his absence will be Crown Prince Billah's flamboyant uncle Jefri, reviled by many as a black sheep whose vices were bankrolled by black crude. He would have to break his self-imposed exile in order to show up for his nephew's wedding - although if he did, the bachelor party would be one to remember. It could take place on his astonishing 152ft yacht, the SS Tits, which used to have two speedboats on board, Nipple One and Nipple Two (long since sold off to placate creditors).

"With their money, they could have cured diseases," one of Prince Jefri's advisers told Fortune magazine, "but they have little interest in the rest of humanity." However, it seems that the Sultan wants to turn over a new (presumably gold) leaf. The time seems inappropriate for an obscene display of wealth to rival the late Shah of Iran's 1971 coming-out party at Persepolis. This wedding - while opulent by most standards - will focus on folk music, ethnic dance and fine Islamic crafts.

Today, all eyes will be trained on Brunei's airport to see which VIPs have braved the tropical storms to pay their respects to the Brunei monarchy. In today's tense world, with the South-east Asian terrorist network Jemaah Islamiya hovering within striking distance, caution prevails at such high-profile events. The Gurkha Rifles and their bomb-sniffing dogs patrol the streets.

The House of Saud will be well represented, and Prince Badar bin Sultan, the Saudi Arabian Ambassador to the US and a Bush family intimate, will hobnob with Asian royal families and heads of state. The latter include Lee Hsien Loong, Singapore's new Prime Minister, plus leaders from the Philippines, Indonesia and Malaysia.

Prince Charles, who won an award for promoting understanding between Muslims and non-Muslims this summer, is a close friend of the polo-playing Sultan of Brunei. But so is Mohamed Al Fayed, the Egyptian owner of Harrods. Neither looks likely to make the trip.