IN Jenny Diski's novel Rainforest, the heroine resigns from her job as an anthropologist in order to embark on a new career as a cleaning lady. After a traumatising sojourn in Borneo's leafy incarnation of chaos, she seeks order in the humdrum tasks of domestic work.

But, outside fiction, surely nobody gives up a well-paid and prestigious job in favour of a menial one unless they are forced to? Ambition has long been considered a desirable quality; salary and professional status are advantages to be courted.

And yet, in these alarming days of executive stress, burnout and compulsory redundancy (British Telecom last week announced the axeing of another 50,000 jobs), the idea of throwing in the towel holds a strange appeal. Philip Larkin recognised the temptation: 'Why should I let the toad work / Squat on my life? / Can't I use my wit as a pitchfork / and drive the brute off?'

When such thoughts first occurred to Gillian Stirzaker, 37, she was a solicitor in a London law firm with an office to herself, a secretary and a salary in the region of pounds 30,000. When she resigned earlier this year, her clients were surprised. When she told them she was going to work for the supermarket Safeway, they were, she laughs, 'gobsmacked'. 'At first they naturally assumed I meant in the legal department. I explained to them that I would be working behind the deli counter; then they were really confused.'

Such a radical step was not taken lightly. When she decided to study law, Gillian had idealistic motives of which she had been largely disabused. 'I had the idea that I would be able to help people - not in as obvious a way as a doctor, of course, but that somehow by virtue of having a few brain cells I could do some good in sorting things out.'

But by the early 90s, she had begun to question whether solicitors really do give their clients value for money. The public perception that they do not - neatly encapsulated in anti-lawyer jokes imported from the States (What is the difference between a lawyer and a catfish? Answer: One is a scum-sucking bottom-dweller; the other is a fish) depressed her further. She worked long hours and weekends, and hated the isolation of communicating with her clients only by phone or fax.

By the time Safeway advertised for staff for their new store in Reading at the beginning of this year, Gillian had come to a conclusion about her highly paid, high status profession. 'I told my mother it was just a living death.'

She turned down the offer of a position in a different law firm because she had already accepted one of 300 jobs at the supermarket for which there were, she later discovered, more than 7,000 applicants. She now works a 39-hour week, at an hourly rate of pounds 3.79.

Safeway's personnel officer, Andrea Morton, says they were looking particularly for friendly staff and that Gillian had impressed her with her attitude to customer service in two interviews and a written test, adding earnestly: 'We are an equal opportunities employer and it would be a form of discrimination to discount somebody just because they seem over-qualified.'

Having withstood the three- month training period ('I'm not a practical person at all and for the first two or three days I was absolutely petrified') Gillian says she 'absolutely loves' her job. She feels she has completely integrated with her new colleagues, and says the initial gulf was easily bridged. 'In the beginning most people seemed interested in whether you had been in work before, not what the work was.'

Any lack of intellectual stimulation has yet to prove frustrating. 'There is a part of me I'm not using; your brain feels what I call 'taut' when you're drafting legal documents, but I'm too busy to feel bored, and in the evenings, I can read all the books I never had time for before.'

She is not blind to the ambivalent attitudes of friends and family to her new social status. 'The people who are my close friends still are, of course. God knows what the others really think, but if you worried about that you'd never do anything.' The English are too polite to mention money, but on hearing the news of her career change, an Australian friend cried: 'Gillian, your lifestyle]'

According to Robin Linnecar, a partner at the London-based career consultancy KPMG: 'All through our careers we hear constantly - in appraisals and on a more informal basis - about the things we can and can't do. Guidance is always given on a skills level. Rarely are we required to examine what we really want to do.'

Often the realisation that a yawning chasm exists between what we want and what we have only surfaces after several years' frantic climbing up a career ladder. Seeing how far we have come, it's hard to admit that the view isn't quite so pretty at the top.

Simon Kirby, 32, spent eight years studying and three years practising as a chartered accountant before deciding that he was bored. Having tried unsuccessfully to inject some fun into the job by moving into the entertainment sector, he began doing odd jobs such as landscaping. When he was finally offered a position as an accountant with a firm of music promoters, he decided not to take it. 'I suddenly thought: this is not what I want to do. It somehow crystallised in my mind that I had gone into accounting because my family wanted me to have a respectable profession.'

Friends now describe Simon as 'a much calmer person'; one new employer, Lindsay Stewart of the PR consultancy Conal Walsh, who hires him to 'stuff envelopes', speaks of him in glowing terms. 'Most people who do that sort of casual work are really lazy, but I would trust Simon with my life. He's intelligent and efficient and everyone in the office loves having him around.'

Acclimatising to the lifestyle changes that comes with a huge drop in income is the hardest thing to cope with. Simon Kirby makes no secret of the difficulties he experienced when his income dropped from more than pounds 35,000 to 'virtually nothing'.

'I do like money and I can't really go shopping for clothes any more in the way that I used to; pounds 50 is precious now, whereas before I knew I could make that in an hour. Some of my friends are thinking of taking the plunge and going freelance like me, and I have warned them that there will be a rocky period in the beginning. But I have more contacts now so I'm getting a steady stream of work. If I have the money to go on holiday, then I can go when I want and the tension and anxiety just aren't there any more. I ask myself, was the salary worth it? The answer is no.'

Moving out of London, Gillian Stirzaker was lucky to have a house in Reading 'as a bolt-hole'. She economises by wearing a uniform and eating lunch for 30p in the staff canteen. The suits she used to buy from Harvey Nichols, the expensive meals in restaurants after work and the taxis she took home from the office were, she says, just different forms of retail therapy to make up for the long hours and constant pressure.

A word of warning is offered, however, by Cary Cooper, Professor of Organisational Psychology at the University of Manchester Institute of Science and Technology. 'Doing a less cognitive job is not necessarily less stressful than being in a position of responsibility,' he says. 'Stress-related diseases like heart conditions occur far more frequently on the shop floor than on the top floor. The working environment may not be so pleasant, for one thing; being on your feet all day somewhere quite noisy, for example. But the most crucial factor is not having any control.'

Not having to take control seems like a blessing to Gillian Stirzaker, however, who says that her brain is now 'free range'. 'It occurred to me recently that there was something at the back of my mind, almost like something I had forgotten to do,' she says. 'Then I suddenly realised what it was - I didn't have anything to worry about any more.' She likens the sense of relief to the feeling of euphoria after an examination, when not having to study any more feels like a huge and unexpected present.

Not that Gillian has closed the door entirely to resuming her law career. A period out of the fast lane does not render professionals unemployable; some manage to make a comeback. Eleven years ago Fiona Lipscombe quit her job as a foreign exchange dealer in a City bank to throw her lot in with her boyfriend as a house painter and decorator. 'I thought it would be fun and good for our lifestyle. We could go travelling whenever we wanted to.' After eight years she was welcomed back into the same hectic department. Fiona feels enriched by her career break. 'You get a lot of time to think when you're standing up a ladder.'

Robin Linnecar talks about the decision to step out of a well worn career path in terms of risk taking versus what is known in the trade as 'leaving the comfort zone' of status and security. Professor Cooper applauds the honesty of those who forsake convention to go for what they want, describing them as 'the heroes of our time'. 'Most people wouldn't admit to the fact that they dislike what they're doing,' he says. 'They wait until they're burnt out or dumped by the organisation because they're not performing well.'

The proof of good adaptation is probably the party test - the moment when a stranger asks for your social credentials. When he first gave up his job, Simon Kirby recalls hedging. 'I used to say, 'Well, actually I'm an accountant, but at the moment I'm doing landscaping.' I got over that. Now I just say I do odd jobs. If people can't tell that I'm intelligent by talking to me, then that's their problem.'

(Photograph omitted)