"I'm just telephoning the palace ..." Then one day, three months later, someone picked up the phone and put me through to Ofa Tu'i' Onetoa, the Palace Secretary. I made my request and then waited - a cautious silence travelled down the line At last Ofa reached a decision. He thought an audience with His Majesty might be possible.So, on the appointed day, I arrived at the Palace in Nuku'alofa. The Palace is a beautiful, unpretentious, wooden dwelling overlooking the sea. A wraparound balcony rises to white lattice and a red iron roof Visitors are shown to a small room off the Palace Office.

On this day, the King's grand-daughter's French lesson is scribbled on a blackboard. Scattered around are photographs of Royals: one of Elizabeth and Philip attending feasts in 1953 with the Queen looking like a porcelain doll clutching a handbag; another of the King, aged 14, breaking Tonga's pole- vaulting record (his record still stands). Two soldiers provide an escort across the Palace grounds to the main entrance hall.Previous visitors - notably Paul Theroux and Simon Winchester - have made much in their accounts of their audiences of the King's legendary size. This is hard to ignore - the man was until recently a generous 30 stone, and he needed two seats at St Paul's for Charles and Di's wedding - but dwelling on it has had the effect of turning him into some kind of sideshow freak In fact, there is great deal more to this king. He is one of a kind - an absolute monarch who in many ways would be more at home in the 18th century.

More than a ceremonial figure, he wields power on a scale unknown to British kings and queens for 300 years. He can create cabinet ministers for life, dissolve parliament and veto any legislation. He is not despotic by nature, but he is, unquestionably, a despot. He rules over a kingdom of 169 islands, and his wish is usually the command of 100,000 subjects. Little happens in Tonga without his agreement; most is his initiative.

"New roads, schools, hotels - everything you see in Tonga began as the King's idea," says Ofa, the Palace Secretary. He forbears to mention the alternative energy programme, the ill-fated oil explorations or the campaign for national weight loss.The King, with his absolute power and eccentric enthusiasms, brings to mind a benign Emperor of Lilliput - or would do, were it not for his size. The figure coming towards me - his arrival presaged by the clacking progress of his walking canes - is not the hulking figure older photos show, stuffed into the shiny suits and bow ties of a Gilbert & Sullivan monarch But he is still a huge man, weighing around 20 stone. It is staggering to think of him mid-pole-vault.What shall we talk about? I immediately realise that the obvious questions, about the growing consensus that Tonga's constitution needs to be brought into the 20th century, will have to be put on hold until we have established some kind of rapport. Better to start with a less challenging subject: his childhood. At what age did he first become aware that one day he would become King? "Soon as I could talk," he replies.