MARGOT is French, 45, and extremely attractive. She walks everywhere at top speed, often accompanied by Shana, the exuberant and affectionate border collie she rescued from death at the hands of her original owner.

Seven years ago, Margot was raped at home by an unknown man wearing a Balaclava. She felt, quite without reason but not unusually, that it was a shameful business for which she must have been to blame and she felt dirty for some time afterwards.

Margot was in the middle of divorce proceedings and living in a council flat with her son, Tim, then aged nine. Traumatised by the rape, she applied for a transfer, and was allocated a flat on the first floor of a Victorian house in a pleasant south London street - my street, in fact.

The flat was in appalling condition, but she accepted it because the elderly couple living on the ground floor made her feel safe. She applied to buy the flat, secured a pounds 45,000 mortgage and set about transforming the chaos and filth into the beautiful home it is today.

To pay for her mortgage, Margot worked part-time in the local library and part-time for an interior designer and antiques specialist. She has taken in foreign students, teaches French to private pupils in the evenings, and still manages to find time to make beautiful papier mache artefacts, which she sells to Liberty and similar retail outlets.

Shortly after Margot and her son arrived, however, the couple downstairs moved to a bungalow on the south coast, and the council moved in Frank, a middle-aged schizophrenic and alcoholic being 'returned to the community' under the care of the Maudsley Hospital.

For the next few years, Margot did her best to be friends with Frank, always giving him the benefit of the doubt when his behaviour was unsocial, always giving way when there was any possibility of a misunderstanding. She is an excellent cook and made soup for him and his girlfriend. She always tried to make allowances for the mess and the stench that permeated the shared downstairs hallway. She was always, without question, the one who cleared up the rubbish lying in the hall and the front garden.

Then things began to change. From being simply dirty, drunk and loud, Frank and his girlfriend began to be abusive. A group of their alcoholic friends began to drop by and they also joined in.

Margot's terracotta pots have all been smashed, she has to clean up the mess left by all their dogs in the tiny front garden. There have been two fires. Once, Margot had to ring the police to escort her from her front door when Frank was shouting abuse at her from the bottom of the stairs and explaining in graphic detail what he was going to do to her when she came down.

Belatedly, Margot began to realise that she was a victim - that she was not responsible for the mess she was living in, any more than she had been responsible for the rape.

She began to wonder whether this was really how she had to live, if life really had to be so hard. She eventually began, in a tentative way, to fight back. On numerous occasions over the past few years she has telephoned and written to the council to complain about the behaviour of its tenant. Finally, a deputation from the council arranged to meet her and discuss the problem. Scrupulously fair, they also arranged to meet Frank on the same day to hear his side of the story.

The man in charge of the deputation was sympathetic to Margot's plight, but urged her to consider Frank's difficulties - he was a victim of society, needed her sympathy and understanding, and so on. What he would like Margot to do was keep a diary of the disturbances . . .

But Margot had been writing to and telephoning the council for months and had had enough. She wanted something done now, not something started. She wanted some peace, she wanted to feel safe. Please, said the people from the council: she must try not to be so emotional - she must try to remain calm.

Margot wants to head for the mountains and live her life simply and alone. She is tired of being understanding, of working so hard just to scrape by and to give her son a decent upbringing. She just wants to go home. But she bought her flat at the wrong time, her mortgage is more than the property's market value, and she is trapped. If it weren't for the tenant downstairs, she might have a chance of selling it. Margot's flat is spotlessly clean, and decorated with typical French flair. But who is going to bother even looking at it if they first have to negotiate the drunks downstairs? Who wants to be subjected to loud music, singing, shouting and invective at three o'clock in the morning? Who is going to want to live with the likelihood of being incinerated in bed at night?

Virginia Bottomley's 10-point plan, announced last week, may make a difference to Frank. It should mean that a professional key worker will ensure that he takes his medication regularly, it may mean that alarm bells ring before he causes himself or anyone else irreparable harm. It is unlikely, however, to make much difference to Margot, whose life is in tatters and who has neither the time nor the emotional energy to write reports, attend more meetings and file more complaints.

I don't see Margot very often any more. Nobody does. Shana goes out with Tim, but seldom now with Margot. Sometimes I ring, but she never answers the telephone. If Tim is in, I ask if she will call me back, but she never does. She doesn't ring anyone back any more. I hope she does get home to France, but I shall miss her when she does and our street will be the poorer.