After 50 years of being spurned, ripped off, corralled together like problem kids and consigned to the worst rooms in the hotel, the single traveller's time has finally come. Rather than being viewed as an awkward aberration in the standard couples-and-families 'system', single travellers have become travel's fastest growing sector, and a phenomenon that tour operators are falling over themselves to catch up with.

The figures speak for themselves. According to a recent Mintel report, 15.4 million Britons are expected to holiday alone this year, up from 9.6 million a decade ago. Companies specialising in independent travel rather than packages have noticed still bigger growth - last year, Travelbag reported a 68 per cent increase in single bookings in the space of just 12 months. The Association of British Travel Agents has even taken to lobbying hoteliers to build hotels with more single rooms. 'We've seen a sea change over the last five years,' says Derek Moore, chairman of the Association of Independent Tour Operators. 'People have become a lot bolder about travelling alone.'

In one sense, the boom is a matter of simple demographics - a result of people delaying marriage and children. Around 39 per cent of the adult British population - 19 million people - is now single and the proportion of one-person households has increased from 18 per cent in 1971 to 29 per cent last year. According to Mintel, the highest growth of singles over the next few years is expected to be within the affluent, travel-hungry 25-34 age group.

But there are other factors at play. Many solo travellers have a partner but opt for so-called 'Greta Garbo breaks', either because they 'want to be alone' or because their partner has different interests. 'I love my boyfriend dearly, but there's simply no way I'm going to waste a week of my annual leave on a ski holiday, which I can't stand,' says Julie Lea, a graphic designer from Birmingham. 'I'm more than happy to take off with friends, or on my own, instead.'

The growing demand for more daring, exotic holidays is also playing a part. While being alone on a week's package holiday to Spain might feel awkward, being single on an overland trip through Morocco or Nepal carries no such stigma. The more adventurous the trip, the more natural it is to do it with a group of strangers. Over the past decade, adventurous group tour operators like Exodus and Explore have expanded quickly, and around 70 per cent of travellers on Explore trips, for example, are single.

But travellers are increasingly happy to go it alone on independent trips too. 'There's far less of the fear factor,' says Jessica Potter of Travelbag. 'People have grown used to using the internet to research their own trips, then book flights and accommodation, so they feel more confident about planning their own trips alone. What we're seeing a lot of now is people setting off alone, but then meeting up for part of their trip with friends who are travelling or working abroad.'

The boom in single travel is being driven by women. In 1986, when Willy Russell's play was first performed, Shirley Valentine felt daring and adventurous to be heading off to Greece to drink a glass of wine in the sun. Twenty years on, Mintel's survey suggests women are just as happy as men to leave partners at home and go away. On adventurous group trips, like those run by Explore, single women make up more than half of travellers, and internet agent Opodo reports 70 per cent of its single clients are women. Earlier this year Friendship Travel advertised for more men to join a singles group trip to St Lucia because so many women had signed up. 'Women today see being single as an opportunity to travel, rather than a hindrance,' says Judith de Witt of Rainbow Tours.

The result is that travel companies are now attempting to work out new ways of attracting singles - a market worth £10.4bn. Last winter saw the launch of Cold Fusion, a ski chalet for 'individuals' in Chamonix, and this season others are following suit. The number of specialist singles tour operators has risen from a couple to at least 10, but they face a growing challenge from mainstream operators, who are targeting solo travellers with moves like abolishing single room supplements.

'At the moment you've usually got to join a group, or pay more,' says de Witt. 'As soon as we get beyond that, the singles market is going to take off to a whole new level.'