This was no mirage: it was one of the film units for the next blockbuster in the Star Wars series. A whole planet of plaster was being constructed in the desert, our guide told us excitedly. To us, a space-age set in the Sahara seemed less incongruous; the sandblasted dunes and eerie moonscapes of the desert are a natural film set in themselves.

Jolting across wadis, the dry river beds that run through the scorching cactus belt, I was on an English Patient desert safari, following in the ill-fated footsteps of Count Almasy and Katherine in the much-praised movie in which Tunisia itself played such a starring role.

Michael Ondaatje's novel was originally set in Egypt, but director Anthony Minghella decided that for the purposes of the film, Tunisia's stunning locations more accurately represented the Egypt of the Thirties.

The film's effects on Tunisia's tourist industry were overwhelming. "Our holiday bookings from the UK went up by almost a quarter in 1997, and continued to increase substantially to well over a quarter of a million in 1998," says Ann Noon of the Tunisian Tourist Office in London.

Tour operators were not slow to jump on the bandwagon, and English Patient desert safaris mushroomed, incorporating locations featured in the film - most are easily accessible to holidaymakers prepared to break away for a few days from coastal resorts such as Hammamet, Sousse and Monastir.

Many of these locations are only a couple of dunes away from those that form the backdrop for the new film Star Wars: Episode I - The Phantom Menace. And if the brooding features of Ralph Fiennes and steamy passion among the sand dunes boosted Tunisia's stats in '97, the number of tourist arrivals this year and next will surely skyrocket after the latest Star Wars "prequel" opens. It has its American premiere on May 19 and opens in Britain on July 16.

It is 20 years since director and writer George Lucas introduced Luke Skywalker, Darth Vader and the 'droids in the original trilogy, thus spawning a generation of Star Wars disciples, a whole new vocabulary and endless jokes about Jedis, R2-D2 and C-3PO. Starring Liam Neeson and Ewan McGregor as Jedi Knights, the action in Phantom Menace takes place 40 years earlier and examines the mystery of why Luke Skywalker's father, Anakin, became Darth Vader and defected to the Dark Side of the Force.

The huge film set in the Tunisian desert was built to represent Anakin's home planet, Tatooine. No mean feat this; everything for cast and crew - tents, toilets, washing machines, elaborate props - had to be transported through shifting dunes and across the Chott, where mud under the salt crust once engulfed a 1,000-strong camel caravan.

To transport the gear, a special road was constructed across the desert, a route our own safari driver thankfully used as a short cut to Tozeur.

I can also vouch for the unpredictable nature of the conditions that virtually wiped out the set, a desert storm of 120mph destroying the entire base camp and most of the "planet" on only the third day of shooting last August.

On our own safari, a sudden Saharan sandstorm caused our vehicle to be bogged down in a dune; struggling to free it we had to withstand the full ferocity of the sirocco that lashed, lacerated and stung our legs and arms, and whipped away hats and sunglasses. By the time we were pulled free, the tracks of our convoy of four heavy four-wheel-drive vehicles had been completely buried.

Like the film crew, we were only too happy to get to Tozeur, 30 miles away, and appreciate the attractions of the lush and beautiful oasis of two million palms fed by 200 natural springs, with the best dates in the country and 14th-century brick houses.

The desert town can even boast a "zone touristique" with luxury Hollywood-style hotels, an interesting museum of traditional Tunisian life and a somewhat ludicrous Arabian Nights theme park displaying mock crocodiles and elephants. Tozeur, where cast and crew stayed during the filming, is to be one of the highlights of the new Star Wars desert safaris.

The leading UK Tunisian specialist, Panorama Holidays, recently bought out by mass-market giant Airtours, has started the Star Wars ball rolling by launching the first four-day safari excursions. The firm already takes more than 100,000 holidaymakers a year to Tunisia and, says Panorama marketing executive Michelle Hamilton, "We're expecting Star Wars to create even more of an impact than The English Patient, so we've rushed out a new programme of excursions."

The four-day Star Wars safaris are already on offer, with only slight deviations from the well-trodden English Patient route. The trips also include hardy excursion perennials such as the Holy City of Kairouan, where non-Moslems may not enter the Grand Mosque, but can practise their haggling techniques over the traditional rugs and kilims that are woven there.

No film designer could ever have invented the troglodyte cave village of Matmata, which kicks off the original Star Wars trilogy and which reappears in The Phantom Menace. On first arrival, there seems to be little beyond bare hills, a police post and a small Moslem shrine, until a voice from below shouts "bonjour", and you realise that you have all but stumbled into a cave dwelling.

Further inspection reveals a lunar landscape pitted with 500 or so craters like a giant Swiss cheese, each crater the courtyard of a family home, with the rooms cut into the walls. Spotlessly clean, some of the caves sprout TV aerials, even garages, and although some of the younger generation have been resettled by the Government in a modern village, Nouvelle Matmata, ten miles away, many of the cave-dwellers have refused to move, claiming that their unusual homes are cool in the summer and warm in the winter.

In order to cope with the tourist influx, a number of cave hotels have sprung up (or down, to be more accurate). One of them, the Sidi Driss, featured in the original Star Wars movie.

"Do you want to see our book of the film?" asks the barman somewhat wearily, as he pushes over the hotel's well-thumbed photo album along with your beer or boukha, the local fig liqueur.

Travelling still further south to Medenine, Tataouine (a real town) and Ksar Hadada, the safari will take in yet another of Tunisia's and the film's strange locations - the "ghorfas", a series of cells or hives piled on top of each other, originally used by Berbers as fortified granaries.

The tours may prove an antidote to the coastal hotels, with their ubiquitous buffets and evening rituals of karaoke and quiz nights, spiced with belly-dancing-cum-folklore.

Not that Tunisia will be the only destination to benefit from Star Wars hype; if you want to get ahead of the pack and see The Phantom Menace before it reaches Britain, one travel firm is already pioneering short breaks to Philadelphia, with cinema tickets to see the film on the first weekend of its release as part of the package.

Extract taken without permission from The Times, April 11th 1999