Is it safe to swim out there? Are there any sharks?” I ask the park ranger.

“Sharks? No, mate,” he answers, “the crocs have eaten them all.”

Typical Aussie humour. I hope.

“No, really, don’t worry, mate,” he assures me, “salties (the person-eating saltwater crocodiles) don’t venture this far south. And all the dangerous marine life lives on the other side of the island. You’ll be the biggest predator out there.”

It’s hard to tell where the joking ends and seriousness begins, because the sports-mad Aussies are still smarting from the loss of the Ashes. This guy might not be averse to sending a Pom to a violent death.

I decide to butch it out. I am on the subtropical nature reserve of Fraser Island, just off the south Queensland coast. The sea is warm and transparent, and I’ve schlepped my snorkel all the way from Europe, so there is no way I am staying dry, crocs or no crocs.

I climb down the steps at the end of the Kingfisher Bay Resort’s jetty and introduce myself to the schools of tropical fish hanging out there, listening out all the while, I must admit, for the Jaws theme music.

Dangerous animals are a popular topic here, because Fraser Island is a Kate Moss kind of place — stunning to look at, but with serious reputation issues. In 2001, a young boy on an early-morning stroll along the beach was killed by dingoes. And in November 2004, the parents of a three-month-old baby found a dingo near the cot in their hotel room.

Today, there are fences to keep the dogs out of the resort’s grounds, and notices everywhere advise people not to feed their children to the wildlife.

Communing with nature, preferably without getting eaten, is what Fraser is all about. It is a 75-mile-long sand dune, rising to 360ft above sea level in places, and is covered almost entirely in rainforest. More than 350 species of bird live here, as do pythons, dugongs (“sea cows”) and the prehistoric- looking ferns that starred in Walking with Dinosaurs. It is practically unpopulated outside of the two main resort hotels and a few camp sites. You can still see why the Aborigines called it K’gari, or paradise.

Even so, sub-paradise would probably be a more accurate description, because the island is also one of Australia’s favourite places for pretending to be Jeremy Clarkson. Any Queensland family with a car that bears the slightest resemblance to a 4WD heads over here on the ferry and spends at least one weekend a year getting bogged down in the island’s treacherous sandy tracks.

This may sound like a paradox — nature reserve and 4WDs — but an off-road vehicle really is the best way to see the island, and the Aus$30 (£13) vehicle-permits fund the park and keep loggers at bay. And anyway, Jeremy Clarkson wouldn’t be that happy here, as there are no metalled roads to make his tyres squeal.

I join one of the resort’s 4WD tours, led by Peter, a khaki-shorted ranger with a perma-smile, the kind of guy it is impossible to ruffle — except, that is, when he has to stop his vehicle to wait while yet another inexperienced, ill-equipped driver is hauled off the track to await help. After our third wait, he gets ticked off by his manager for using fruity language over the CB radio.

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