AS SHAM SUB-CATEGORIES go, the coaching sensation — and it surely is that — remains in its infancy. True, an elite corps of top managers has long sought counsel from an elite corps of personal consultants.

For the right price the right person could even get Tony Robbins — whose one-to-one clients have included Nelson Mandela, Mikhail Gorbachev, Margaret Thatcher, François Mitterrand and Bill Clinton. But it is only in recent years that coaching has gone mass market with an astonishing trajectory: a growth rate that The Economist in 2002 estimated at 40 per cent a year.

In business settings, coaches are now so sought after that their hourly earnings often outpace those of counselling professionals with hard-won credentials. A top executive coach may charge $400 (£225) an hour or more, easily exceeding the going rate for most established psychologists or psychiatrists.

So just what qualifies someone as a life coach? A better question might be, what disqualifies someone? “There are no bedrock qualifications, no unified approach to coaching, no clear and unimpeachable credentialing,” Warren Bennis, a professor of business administration at the University of Southern California’s business school, told me. “Basically this is a business that flies under the radar screen of any sort of oversight.”

The laissez-faire nature of the enterprise is clear in that even many of the top websites that offer life coaching also give the visitor the option of becoming a life coach. Indeed, the first link on www.life-coaching-resource.com, even before the ones that click you through to the coaching help you presumably sought, reads: “Start your own coaching business.” Imagine consulting a site for medical help and being greeted by the offer “Would you like to find a doctor . . . or become a doctor?”

Many of today’s life coaches were doing something else before the turn of the millennium and, in a fair percentage of the cases, that something had little to do with counselling, therapy or training of any kind. “Whenever you get increased demand, and supply comes to meet it quickly, it doesn’t necessarily have to be of the best quality,” says John Kotter, a professor of leadership at the Harvard Business School. If the demand is high enough, all kinds of muck will flow into the market.”

That river of flowing muck has not prevented a steady complement of otherwise-savvy people putting their faith in coaching. According to Fortune magazine executive coaching is “the hottest thing in management”. Managers hire coaches to facilitate divisional change (and deflect the blame that often accompanies it). Mid-level staffers, no longer anticipating the continuity of employment or professional TLC that once was expected from the business world, have turned to coaches for guidance on how to improve their morale and make better, more personally relevant decisions — both on the job and off.

Personal coaches are “not just sticking to corporate matters”, Bennis told me, “and that’s really the whole point. They’ve widened the lens. They’ll ask questions like, ‘Does this job make you happy?’ ‘Should you even be in this line of work?’” Coaching as we now know it debuted in the 1980s, probably with a Seattle financial planner, Thomas Leonard. He realised that his successful young clients, though emotionally “whole” and hardly candidates for traditional psychiatry, nonetheless seemed to need more from him than just the usual tips on how to invest and shelter their formidable incomes. Years later, he would remember a moment of truth when he asked some of them if they wanted to talk more holistically about life. ” They jumped at it,” Leonard told Fortune. “They just wanted to brainstorm.”

His career shifted from financial planning to full-time brainstorming, which at the time he called “life-planning”. As mergers-and-acquisition mania took hold and widespread corporate downsizing destabilised the American job market, the hunger for Leonard’s services grew. Some of his clients wanted to kick around other ways of making money, some wanted to learn how to de-stress, some wanted a pat on the back, some wanted a shoulder to cry on. Somewhere along the line, somebody used the word coaching, and within a few years, Leonard was coaching other prospective coaches, who were often corporate burnouts or refugees from other areas of the conventional business world.

In 1992 Leonard kicked off a formal coach-training programme he dubbed Coach University. Coach U, as it came to be known, today offers more than 50 “teleclasses”: courses in coaching methodologies that are conducted via conference call.

What such instruction prepares coaches to teach can be hard to say. Life coaching is such a slippery enterprise that even explanations of its appeal sound vaguely... well, slippery.

The life coach wears multiple hats. He or she is part consultant, part oracle, part cheerleader, part provider of tough love. Not all of these hats always fit as well as they might.

Observers say that these therapists-sans-portfolio often function as full service shrinks, though the coaches themselves vehemently deny any such thing, since those activities would constitute practising psychiatry without a licence. “I know the boundaries,” one independent life coach told me. “I’m not here to put people in touch with their inner child. I’m here to help them as a tactician.”