"Wanted. Young, skinny, wiry fellows not over 18. Must be expert riders, willing to risk death daily. Orphans preferred. Wages $25 per week."

This is how the new edition of Work Your Way Around the World begins. Fortunately the vacancies in question have long been filled - the advertisement was placed in 1860 by the Pony Express. The book's author, Susan Griffith, found the poster at a museum in Washington DC. But some of Britain's present- day travel enterprises are reporting alarming staff shortages.

Travel has never been among the world's best-paying industries, but a wage of pounds 360 per month including board and lodging in a beautiful part of England or Wales seems a reasonably attractive prospect. Yet Edwina Edwards of the Youth Hostels Association says she is having trouble filling the 400 vacancies for assistant wardens this summer.

"We're getting plenty of people responding to our advertisements, but many of them see what the job's like and then don't bother to fill in the form. Worse still, some of the people who do apply and succeed at the interview turn down the job when it's offered."

Hang on, though - why do you need staff, anyway? What about the chores that hostellers are supposed to do? Apparently there has been some customer resistance to the old-established routine of an hour or two of housework.

"Expectations have changed, and now we rely on voluntary help," says Ms Edwards - though in the last hostel I stayed in, the resident warden didn't give the impression that there was a substantial element of choice on the subject of cleaning the kitchen.

It seems that southern softies like me are proving less than co-operative in filling the vacancies.

"The north-south divide is really quite dramatic. We're well staffed in the north, but still have a number of vacancies south of the Peak District. Some people think that working in a youth hostel will be an extended holiday, and when they find it isn't they look for something else."

In my experience, a lot of them go abroad. Every backpackers' hostel from San Diego to Sydney seems to have at least one British employee. But if cleaning up in Coalport or landing a job in Land's End appeals, call Edwina Edwards on 01426 939216.

Should rafting the Zambezi or trekking across the Andes appeal more, then the person to talk to is Moira Welikanna (0171-370 6951). She can't get the staff these days, either.

Ms Welikanna handles recruitment for the adventure travel company Encounter, and is trying to recruit expedition leaders.

The pay is similar to the YHA - board and lodging plus about pounds 100 a week, which buys more in Ecuador than it does in Edale. "The basic job description," says Ms Welikanna, "is simple: to take people safely and enjoyably from A to B". But you are on continuous duty 24 hours a day, responsible for 20 paying passengers - and may have to sort out anything from a clogged oil filter on the overland truck to armed insurrection (though not usually among the clients). To help you cope, you get up to a year's training, half of it overseas.

The qualifications are straightforward: "You've got to be over 25, and able to think on your feet, stay very cool and keep your sense of fun."

John Leivers has been an expedition leader for 10 years. "The best thing is the sense of achievement when you spend all day going up a mountain on some of the worst roads on earth, and finally discover wonderful volcanic scenery. The worst thing is when the truck breaks down half-way up."

The joys of working to travel are confirmed by some readers of the last edition of Work Your Way Around the World. Angie Copley writes from Caracas: "If I hadn't spent my last pounds 10 on your book I'd never be where I am today. I started to realise that what I had previously thought was impossible, of travelling and working as well, could really happen."

It couldn't happen now: the price of the new eighth edition has risen to pounds 10.99.