At 7.24am, the maiden voyage from London to Sydney began from beside Cleopatra's Needle on the Embankment in central London.
Unlike its transportational ancestor - the pink-and-purple psychedelic Magic Bus calling at Istanbul, Kabul and all ashrams to Kathmandu - the Latvian-registered coach looked almost too ordinary. It is a 53-seater that would not seem out of place ferrying parties of pensioners to Paignton.
But the bus is attempting a journey that no other commercial undertaking has achieved: a 24,000km trip from London WC1 to the Sydney Opera House. The OzBus is scheduled to arrive 12 weeks later almost to the minute, at a precise 5pm local time on December 9.
For each of the intervening 84 days, it will average just 290km, allowing plenty of time for sightseeing.
By the time the sun rose over the Thames, most of the passengers were ready and waiting, sizing up the strangers who would be their companions for nearly three months.
Plenty of parents and lovers, weepers and wailers turned up as well, including an Australian contingent who appeared to have come straight from the pub. The excitement had been heightened by the months of anticipation.
Since the first ticket was sold in January, some prospective travellers have been keeping online blogs. One, "Andy S from London", wrote "It all seems like some weird daydream that I will wake up from any minute".
The crew of three comprises two drivers and an Aussie tour leader, Janelle Connor, whose duties will include steering the party across some of the toughest borders in the world: Turkey-Iran, Pakistan-India and Nepal-Tibet.
Speaking as the bus trundled through Belgium, she described it as her dream job. "I heard about it in February and begged them to let me do it. It's a very hands-on group, so it's not like other tour jobs.
"I know people are worried about Iran, but it's all part of the adventure."
The businessman who conceived OzBus is Mark Creasey, from Crawley in West Sussex, who has interests in property and catering. He spent some time backpacking in Australia, but looked for a slow bus home in vain, not least because of geopolitical barriers.
"I tried to take the slow route back about 15 years ago, but I got as far as the borders of Thailand and Burma, and they wouldn't let me in. A couple of years back I realised that the trip was now possible from end to end, and in a moment of madness I decided to set it up."
Considering the large chunk of time needed for the venture, the passengers are a remarkably eclectic group. This is not your average gap-year gang. Apart from one 19-year-old, there are no other post-school, gap-year students on board, partly because the price of the 12-week adventure puts it beyond most school-leavers.
Each of the passengers has paid £3750 ($10,600) for accommodation, most meals and transport. The hop between Bali and Darwin in northern Australia will cost them another £175; the bus is to be shipped by cargo vessel, while the passengers fly.
Speaking from the bus as it neared its first stop, Danny Lawrence, 19, who saved up for two years, said the atmosphere was jubilant.
"It's been a pretty tiring day, but I still know it's the best decision I've ever made," he said.
Bill Fisher, 55, has been living in Britain for 25 years and will be going home to Adelaide for good when he finally arrives in Australia.
Some of the passengers will have been congratulating themselves on the modest carbon footprint they will leave behind, but the impact of their journey will be almost doubled: the bus is to be driven back to London empty.
Creasey's dream is to eventually have one departure a month from London and Sydney.
The trip has proved so popular that a "relief bus" will depart at the same time next Sunday. Among the passengers travelling on this second bus will be another couple who don't fit the usual backpacker mould.
Pete Smith, 60, and Anne, his 57-year-old wife, who will be celebrating his retirement from teaching in Sheffield, sound as excited as any teenager. "I always wished I had gone to Australia in the 60s, and I'm really looking forward to it all," Smith said.
The OzBus appeal is that it offers a "slow-travel" alternative to the fast flight, through Europe, Turkey, Iran, Pakistan, India, Nepal, Tibet, China, Laos, Thailand, Malaysia and Indonesia to Australia.
Creature comforts are not to be found on the OzBus. More than a third of passengers' nights will be spent under canvas and the remainder in budget accommodation, or seated (very upright) in their coach seats.
On one notable day, they will have to drive 560km from Iran to Pakistan in one go, to avoid stopping in bandit country.
It is this leg that the crew fears most, but Tony Wheeler, whose original overland trip across Asia led to the creation of the Lonely Planet empire in the 1970s, sees China as a potential problem, too. "Foreign-registered vehicles I've seen in China all have to be registered in China as well. You see a lot of cars in Hong Kong sporting two licence plates."
- INDEPENDENT