The riddle of Percy Island; Australia

What a bastard. He just said goodbye, handed me a fiver and disappeared. He was my stepfather. I was 12 years old. Thirty five years later, there I was in Australia on the trail of the man who walked out on my mother, me, and my two younger brothers.

In 1961 we were all living on a farm in north Devon. Today Andrew Martin, Old Etonian, former Olympic athlete and runaway husband and father, lives on Percy Island, seven square miles of tropical paradise on the Great Barrier Reef.

Percy Island lies some 70 miles off Mackay, one of three islands that make up the Northumberland Group, "discovered" in the early 18th century by Captain Cook. Not that he ever visited the islands - he sort of sailed by, and named them after the Duke of Northumberland.

But many others have visited the islands, including escaped convicts, murderers, treasure hunters and runaway dads.

Reaching the islands is an adventure in itself. There are no cruise boats, no airport and no guide book. Which is, of course, why the Percys are still unspoilt. Many have wanted to cash in on their tourist potential - miles of sand, coral, safe swimming, rainforest, and rare plant life. However, they are under the protection of the national parks and you require a permit to visit.

I arrived there after a seven-hour journey in a 60ft ketch, a former pearling lugger. The Ruby Charlotte picked me up from a dot on the map called Carmilla Creek, 120 miles south of Mackay, a mangrove-infested lagoon of milky blue water which appeared to be deserted but for discarded "tinnies" scattered about the foreshore. A large sign warned of the dangers of box jellyfish.

Life on board was tranquillity itself at first. As I sat under a balmy sky in a wicker chair tied to the deck, drinking home-made mead (brewed on Percy from the island's honey), it all seemed a far cry from winter back home.

Five hours into the trip I was clutching a life-jacket, throwing up and praying for salvation as the boat pitched and rolled in 20ft seas full of sharks. Well, that's the way I it seemed to me.

I opened my eyes to see a stunning beach fringed with palm trees. The boat was cruising through calm, turquoise water towards a jetty and dry land.

Most visitors to the Great Barrier Reef head straight for the more easily accessible tourist destinations such as Magnetic, Green and Great Keppel Islands, ignoring the chance to visit the hundreds of less well known but equally spectacular gems, such as the Percys.

There are three islands in the Northumberland group. Two are deserted. Andrew Martin lives on Middle Percy. We anchored in a cyclone-proof lagoon, one of the few safe anchorages for the thousands of boats that cruise these islands.

On the beach was a huge A-frame building providing overnight comfort for yachties, from where Andrew Martin earns a meagre living by selling home-grown produce such as mango chutney, honey, beer and fresh fruit. A rudimentary shower allows sailors and the occasional other visitor, like me, to freshen up - when there's water. When I was there it hadn't rained for months and the water tank was dry. The beach was deserted but for a lone bull, one of a small herd of Indian cattle introduced to Middle Percy.

The first people to set foot on the island, in the early 19th century, had rather more to contend with. Four white botanists were eaten by the then resident Aborigines.

Next came three gold-diggers, attracted by the huge veins of quartz visible in the cliffs. One was murdered, one committed suicide, the other simply vanished. Then the bodies of several escaped convicts were found washed up on the beach, after the yacht they'd stolen from the Bishop of Tasmania was wrecked on the approach. Then there was a character called Jimmy Joss, who hid a thousand gold sovereigns and couldn't remember where. They've never been found.

After Jimmy came ex-Indian Army veteran Colonel Armitage, who grew coffee, and, in 1922, the White family, who remained on the island until Andrew Martin bought the lease in 1963 for the equivalent of pounds 5,000.

It's three miles from the makeshift jetty to the house. The road - a rock-strewn track that gives you a feeling of being in a liquidiser - snakes its way through forest and creek to a large clearing in the middle of the island. The house - a traditional Queenslander built on wooden stilts - looks the picture of luxury. It isn't.

David Attenborough could have made an entire TV series, just by focusing on my room. The dim light from the battery power was enough to make out a 6ft-long brown tree snake making its way to bed - my bed.

I put my head on the pillow, only to hear a scratching sound. Using a torch I looked under the bed. Hanging from the springs were - and I counted them - 15 bats.

I reckoned there was more wildlife inside the house than outside, and that's where I retreated.

The next day, after a breakfast of goats' cheese, goats' butter and goats' milk, I headed for the sea and a blissful hour swimming among angel fish.

The island is stocked with sheep, cattle, kangaroos, emu (just one) - and goats. These are regularly shot to provide meat for the residents and their dogs. I never want to see a goat again.

There were lots of snakes - but Andrew said they were harmless. I reckon that nothing in Australia is harmless.

After two days I hitched a ride on a boat to a neighbouring island (20 miles away) where there is an airstrip. As we took off I reflected on my greeting from the King of Percy - his phrase not mine.

Andrew had stood there, in a pair of mauve Speedos and a filthy cotton T-shirt. He was supported by an upturned broom which he used as a crutch.

"Hi," he beamed. He shook me by the hand. "I'm glad to see you."

"So," I asked him "Why did you leave us?"

"Ah, that's a difficult story ... how's your mother?"

The bastard.