When Cliff Richard and friends departed in a bus from London in the musical Summer Holiday, they expected no more worries for a week or two.

Tomorrow, 38 adventurers will wave goodbye to Big Ben and the London Eye as they board the inaugural London-to-Sydney bus service, a three-month adventure.

To help to ensure that their trip too is worry-free, the organisers will be bypassing the hotspots of Afghanistan, Burma and East Timor. But the exotic route takes passengers past Gallipoli, the Taj Mahal, an Indian tiger reserve, Everest, Ko Samui and Uluru.

The bus tickets, at £3,750 each, sold out in two months. A second bus departs next week. The aim is eventually to provide a regular monthly return service.

Mark Creasey, 38, the property entrepreneur behind the OzBus, has nursed the ambition since he tried to return overland from a backpacking tour of Australia in his early twenties.

The world was a more forbidding place then, with communist China, Laos and Vietnam largely closed to visitors, and he gave up. Today the route is mostly an open road. Although the Chinese authorities bombarded the organisers with red tape, the Pakistanis and Iranians embraced the idea.

The OzBus departs from the Thames Embankment at 9am. The secondhand continental tour buses have safes, stereos, small libraries, cooking equipment, crockery, and fridges or cool boxes. Passengers are advised to bring basic first aid kits, insect repellents, malaria tablets and a 12-week supply of condoms.

Many nights will be spent under canvas. In Iran and Pakistan, they will stay in hotels for safety.

There are two drivers: a 50-year-old Belgian man who has driven trucks over the Sahara and a 28-year-old New Zealand woman with experience of a range of European terrains.

A third of the travellers are British holidaymakers and a third Australian backpackers returning home. To everyone’s surprise, the rest are from Ireland. “They are natural travellers and probably more open to wacky ideas,” Mr Creasey said. Many Irish people received a £13,000 windfall from a government-backed savings scheme last year and some are blowing it on the trip. OzBus says that it will begin one of its Sydney-bound services next year in Galway.

The oldest traveller tomorrow will be Tricia Roach, 69, a retired protection squad assistant and grandmother from Tadworth, Surrey. “It’s something totally different to any other trip I’ve been on, it covers many countries, albeit only a day or two in some, so there is a taste of different cultures and food,” she said in an e-mail yesterday.

One of the youngest is Danny Lawrence, 19, from Stevenage. While most of his friends have gone to university, and so have no money, he has become a chef at Waitrose and saved a tidy sum.

He has never been farther than Lanzarote and this is his first camping trip. “Doing this trip is a way to look for things that will interest me and give myself time to think,” he said.

Many of the passengers will be posting blogs of the trip on the internet.

Only one leg of the journey, from Bali to Darwin, is by air. The £175 flight is added to the price. The bus will be shipped to the Northern Territory, where the overland journey resumes.

Although the media have latched on to the low-carbon footprint of the bus, Mr Creasey says frankly that none of the passengers mentioned green travel as their motive.

Rather, this is a return to the kind of bus trip taken by a generation of intrepid youth after the Second World War, before paranoia closed down borders. “It was very popular in the 1950s and 1960s,” Mr Creasey said. “A lot of the route is the same as the hippy trail.”