THIS is what happens when you ask Eileen Gibson a difficult question about her extraordinary job. Her eyes focus on nothing for a second or two; then she nods as if some fact has just clicked into place; finally, she offers an even-toned piece of candour that appears to confirm your worst suspicions.

'As we got nearer the time to start,' she says, 'things got worse. We became more and more anxious. There were sleepless nights. We had a holiday together just before they moved in and I remember thinking we might never be able to do this again. . . .'

Which is exactly what you expected her to say. Mrs Gibson has 'adopted' three mentally handicapped adults. This is her job. For a weekly payment, which she is reluctant to discuss (though it is in the region of pounds 200 per person), she, her husband, Rothnie, and 11-year-old son, Jamie, share their West Sussex home with two men and a woman who were previously living in a hostel. This is not just for a few days or on certain conditions. It is a merger of lifestyles, and forever.

To those who treasure privacy and nurse an unease at mental handicap, it would be a double nightmare. Mrs Gibson is living out the reality and seems cheerful enough. We are sitting in a smallish, neatly decorated room with a big television in one corner and enough soft chairs around the rim for all of us: that is, the Gibsons, plus Colin, Pam and Brian, who are the 'guests' - a term you want to use but the Gibsons never do. In fact, they go to huge lengths to avoid any group word. Colin, Pam and Brian are always just that - Colin, Pam and Brian.

They seem pleasant, shy souls, anxious to please but a bit overawed by the solemnity of an interview. Colin Swepstone, who walks with some difficulty, is 48. Pam Wells, 61, lived with her mother until she died; Brian Alibaster is 46. Their backgrounds seem rather sadly hazy - social workers have complained that notes on one of the men amount to no more than half a page - but all three previously lived in a council hostel, which apparently they found noisy and quite alarming.

They say they are happy now and you can just see how small-scale living would suit such gentle people. They listen quietly for two hours, sometimes laughing politely, occasionally offering a comment - on the state of their bedrooms, for instance (Pam has her own, Colin and Brian share), which are crammed with television sets and stereos. Mostly, they sit with infinite patience while some difficult and embarrassing stories about them unfold.

Mrs Gibson thinks more people should do this sort of work and believes few will accept laundered truths, so here come the warts, and Colin, Pam and Brian, who are 'family', can listen, too. It is rather dignified, though occasionally squirmy. For instance: 'I know that a neighbour was quite upset when she heard what we were doing,' says Mrs Gibson. 'I heard that from someone else but ignored it. She said she was going to move. Then she came to me and said she was sorry, she had said it but not now. She never hears them and is happy. But someone else here has reported us to the council.'

In fact, the arrangement is part of the Government's care in the community programme and is overseen by West Sussex County Council's social services department. Families all over the country have been 'adopting' mentally handicapped adults for years, but as impersonal hospitals and homes continue to close, the numbers of those going to ordinary homes are increasing. West Sussex came late to the scheme and has only about a dozen 'people with learning difficulties' placed with families so far.

Mrs Gibson is 42, and until July worked as a childcare officer at a centre for maladjusted children. Before that, she worked with handicapped adults, a job she enjoyed - 'because they were very loving and affectionate' - though she had no professional qualifications. Then came the life-blip.

'I was getting fed up with what I was doing,' she says. 'I found I missed working with mentally handicapped people and wasn't getting the same sort of affection from the boys I was working with - they were very aggressive. Mentally handicapped people accept you as you are and it is very rewarding.

'I have a friend who was doing exactly the same as I'm doing now and they had such a lovely lifestyle. It was more relaxed and I thought I would like to do it, too.'

Agonised discussions followed, not just with Rothnie (who manages a car body shop) but with the whole extended family, including grown-up children from previous marriages, and their own mothers. Many were wary. Some said they didn't think they could visit and feel at home. One said that being at home all day would turn Eileen into a 'stick-in-the-mud'. Jamie said flatly that he did not approve, because it meant moving across the road to a bigger house. How much these protests were masks for other concerns, no one can tell.

'The biggest fear,' says Eileen, 'was that we would all move in together and just not get on.' Exploratory meetings with Colin, Pam and Brian did not go flawlessly: 'They would come in and sit down and we would bring in some tea and there was nowhere for them to go. In that house we only had one room to meet in, and it was just Roth and me waiting on them,' says Mrs Gibson. But they persevered.

Colin, Pam and Brian are mentally handicapped, not mentally ill. They can read and write a little, and Colin particularly chatted about life at his training centre in those early meetings. They laugh about this now, saying he's a right old chatterbox. Mrs Gibson says they all grew fond of each another in the weeks that followed. Final commitment came with the move to the bigger house across the close, which meant increasing their mortgage from pounds 37,000 to pounds 47,000 and persuading Jamie to leave his old bedroom.

Colin, Pam and Brian moved in at the end of August, and at once a sequence of dramas and irritations began - again, exactly as you might expect. Colin was 'lost' for two hours during a shopping trip. Mrs Gibson and Pam fell out over domestic arrangements. Colin, who is epileptic, had fits after being told that he was to meet the local MP in an attempt to enlist his help over funding delays.

These are minor horrors, perhaps, but the change from institutional to home life brought additional problems. 'Colin, Pam and Brian would take a seat and call it 'their' chair,' says Rothnie. 'You can't have them saying, 'Excuse me, you are sitting in my chair'.' Eileen says, 'It seemed we were nagging all the time. It was hard.' Harder still was finding the balance of attitudes: was she friend, mother, fellow adult, or warden? It was embarrassing giving adults pocket money each week - yet when she mixed this with cash for fares, they became confused and spent too much. It sounds difficult, but Mrs Gibson insists that it was no more anguished than the compromises of marriage.

Routines have smoothed, she says. It works like this: during the day, the three are away at a local day centre; in the evening, they share the living rooms but are asked to go to their bedrooms - though not to bed - at 9.30pm. Once a week they all go to a local social club, Jamie as well; once a week they play bingo at home. On Thursday nights, Colin, Pam and Brian attend their own club, and at weekends they share all treats. Next year the six of them will go on holiday together, though the Gibsons will later go away by themselves, despite their earlier fears. There are minor rules about who does what chores and one major proviso: the three are never left alone in the house. But this is eased by the fact that, under the terms of the arrangement, Mrs Gibson pays for a helper, Becky, to come in for 35 hours a week.

It is oddly unnerving, hearing such details outlined so calmly, watching Colin, Pam and Brian smile politely as the facts of their care are listed. Their whole lives, the Gibsons' too, are wrapped up forever by details, which many might find intrusive; yet strangely there is no sense of suffocation, certainly not of regret.

'It obviously changes your way of life but there are many positive things,' says Mrs Gibson. 'We do get on. We learn about each other every day. I enjoy what I'm doing. It must be a motherly instinct in me - I find it very fulfilling. If the worst happened they could go back into care, but I just can't imagine that.'

More concretely, she makes a profit from the arrangement, and while her last job involved travelling and shift work, here she is at home and the regime is gentler. These are the things you do not expect her to say. She is dwelling, not on embarrassing details but on a way of life with simple benefits: no angry boys; always being there when Jamie comes in from school. The Gibsons have grown closer as a family, too. Eileen and Rothnie praise each other for being 'brilliant' at adapting, and both are obviously proud of Jamie, who embraced the change and now makes a point of introducing Colin, Pam and Brian to his friends.

Colin, Pam and Brian say they are happy, and you feel this must be true. Any routine that means they no longer have to bag a chair must be a step up. But how many people would be prepared to offer them that privilege? That's the point, really. Mrs Gibson says she is not special, but you are left wondering about that. As I leave, Jamie is going through Colin's photograph album, and the two of them seem relaxed and happy, head to head over the book. It seems a naturally friendly act, a good omen. Actually, it's a little bit shaming.

(Photographs omitted)