"Yeah, I've rolled a couple of vehicles over the years," says Reg, sombrely, as our bus tilts worryingly on a rock and dodges a five-foot-long lizard. "Worst was in the middle of the Western Desert. You know that Midnight Oil song? 'The Western Desert lives and breathes, in forty-five degrees'? Yeah, that's the place. Couldn't have been any more isolated if I'd tried. We weren't even going fast, we just hit this wet patch on the road, and because the bus was so top-heavy, it stopped and then it rolled right over. It would have been fine but some fat bloke landed on this other chick, broke her arm. Middle of nowhere, like hundreds and hundreds of miles.

"And the problem was the Flying Doctor aerial was upside-down on the bus, buried in the mud. So I had to bend it around, eventually I got the faintest signal, and they came and flew her out. After that it took five hours for the police to reach us, we were that isolated. And they took all the passengers off, and just left me for the night with the van, me and this English guy.

"So the police disappear, and this English guy says to me, 'you know, before I left, I had this major nervous breakdown. I mean, really lost it.' So I thought, shit, better get the rum out. So we sat there in the middle of the bloody desert, drinking this rum, with me thinking he's going to flip out and pull a knife or something. And you know the next thing he said? He said, 'this is the best tour I've ever been on! I never had this much fun before in my life!"

It sounds, from a distance - and filtered through Reg - like the ravings of a mentally unstable man with heatstroke. But at closer quarters, you begin to see what he means. Reg (whose unscheduled roll, for which he was blameless, was with a former employer) leads five-day treks around central Australia for a company based in Alice Springs. He takes small posses of well-to-do backpackers and adventurous travelers on a tight deadline around the sights of the country's centre, from Alice Springs to Ayer's Rock and the Olgas (more properly known these days as Uluru and Katu Tjuta), to the King's Canyon and the less well-trodden oddities of the Western McDonnell mountain ranges that lie due west of Alice.

These trips lead to unexpected discoveries, not all of them about Australia. For one thing, you get to know facts of magnificent irrelevance about countries that you're not even in. Everyone else on the five-day trip with me was Swiss-German, for example, so I now know the Swiss-German words for moose, mouse, stubble, bumfluff and cheers, along with sundry facts about Swiss national service and the precise location of the coldest town in the nation. One of these facts came to light when the very unSwiss-German sounding Valentina came storming out of the kitchen area at one of our stops, bellowing that there were two moose running around on the chopping boards next to the sink. Establishing the veracity of this state of affairs took the better part of an hour. Moose, phonetically speaking at least, actually means mouse to the Swiss; should you wish to refer to a certain broad-antlered Canadian beast, you have to say elk, but with sufficient emphasis on the "k" to suggest your life depends on clearing your throat.

In any event, with or without the happy chaos of miscommunication, the sights of Central Australia are exceptional by any measure. You don't need another article to tell you of the special weirdness of Uluru with its changing colours in the sunrise and sunset. It is every bit as wondrous as you could possibly have been led to believe, and still more spiritual and strange. But that's what you expect. What the unhinged Englishman had cottoned on to was the really uplifting business of being in the centre of powerful, threatening, sparse and isolated country. It's what the travel writer Pico Iyer once described so well: the irrational need for adventure that means you only feel close to nature when you're actually close to death.

For us, it came on the third day, on the Mereenie Loop Road. Even the name is perfect: something about the number of letter "e"s. This is a three hundred kilometre dirt road through the scrub and spinifex from the King's Canyon round to the settlement of Glen Helen, skirting well to the west of the North-South highway that links Darwin to Adelaide via Alice. There's really nothing to be grateful for in what happened. We were hours into the journey, bouncing along in the desert, endlessly straight red dirt roads snaking before and behind us like an Eagles album cover, and the air conditioning had already been dealt its fatal blow from a tourist head by the time things started to happen.

First a hire car came the other way down the road, its headlights flashing madly. We stopped the bus and the car pulled up in line with the window. In the front were two French people, agitated and speaking quickly; in the back were two Germans bloodied and bandaged but basically all right. There had been an accident further up the road, they said; a car was on its side across the track. Reg fired up the satellite phone and put a call through to King's Canyon, telling the emergency services to start heading north to meet the Europeans on their way in, and then we headed on ourselves.

Twenty minutes later we saw the car, on its side as promised, blocking half the track, miles from anywhere. Nothing else had passed us in the meantime. The Germans had been lucky anyone had found them at all. The car's windows were out, and it looked fantastically insignificant, sullied in the dust, meaningless in the landscape. But a man was there already in a Ute. The police were on their way, he said, with a chain to pull the car level again. He had the baggage from the car in his truck and was about to take it to them. Across the hundreds and hundreds of kilometres, where the only road signs from start to end carried the words "LIFT UM FOOT UP" daubed on a board by a bend, followed, twenty yards further on by "PUT UM BACK DOWN", the system was working. This time.

And then smoke. Palls of black smoke on the horizon, clearly near the road. A bush fire. When we reached it, it was nothing: a curio, a photo opportunity, and we duly stopped and hopped in to the bush, snapping away at distant flames. Reg started lighting his own fires at the roadside, backburning to use up the scrubby fuel before the blaze reached it, thereby reducing the chance of the flames leaping the road. I've got the photos now: very disappointing, glimpses of crimson in the scrub. Then the film ran out.

In the thirty seconds it took for the film to rewind, everything changed. Five of us were standing on the top of a trailer hitched to the back of the bus and, almost without us noticing, suddenly the fire had reached the road, just behind us. Now the fire raged - licks of flame leapt forty feet in to the air, bending and shifting and cracking. The heat was a solid wave, and it was moving our way. "Better move the fucking bus, fellahs," announced Reg, and it would be fair to say we felt panicked as the five of us queued to climb the ladder off the trailer, one by one.

We drove on, and by the time we were on higher ground an hour or two later, a thick column of smoke was visible for fifty miles behind us, covering an area the size of my home town, spreading and spreading and spreading.

And next, a thinner column, ahead on the road, spinning and reaching the sky.

"Reg?"

"Yeah, bro?"

"Tell me that's not a tornado."

"Where?"

"Where? That bloody huge thing that looks a tornado, right in front of the bus."

"Ah, yeah. Twister, mate."

It wasn't full of cows, or oil tankers, but it was a twister nonetheless, and Reg's solution was to drive right up to it, climb out of the bus and jump in to the middle of it. He did a few rotations, apparently involuntary, and staggered back in, covered with dust. "Better than a shower, bro."

We reached the Glen Helen lodge no later than four. I couldn't think of many other times when I'd seen rolled trucks, bush fires, twisters, and just endless miles of nothing in a single day, or ever in my life put together, for that matter. These delights weren't on the schedule. The web sites and the brochures don't tend to advertise things that can kill you. But it did it for me. I just felt more alive.

The people in Glen Helen were more stoic. Caught in a pool tournament with a bunch of helicopter pilots in the only pub in an area the size of Belgium, one of them was particularly unimpressed. "People get in to four-wheel drives and they think they're indestructible," he said. "The only thing you can say for sure about a four-wheel drive is that you can get yourself further into the shit than in a two-wheel drive." Then he paused to swat a grasshopper the size of a plate off the cue ball, flattened down the piece of duct tape that was holding the baize together at the D, and hammered home the black.