Why nanny left me holding the baby: Bella Allcroft was angry when her children's help disappeared. Then she discovered the sad truth

Last month our nanny disappeared. She left the house one Wednesday night, smiling and waving, talking about tomorrow's plans with the children. We haven't heard from her again. I haven't been able to stop thinking about her.

Thursday morning came and Lisa (not her real name) failed to show. She was our daily nanny and cared for our daughter, aged five, and baby son. A shy girl, originally from Devon, she had only been with us six months, but relations were good and she seemed happy. For a Christmas present she had offered to look after the children while we went away for a weekend. I had already begun to pack our bags when she failed to appear. My husband raced off to take our daughter to school, leaving me holding the baby.

I rang Lisa's flat, left a hopeful message on the answerphone and imagined her on the bus, stuck in traffic. Throughout the day I heard nothing, despite repeated messages. By 5pm I was convinced she had been murdered on her way home the night before. I had taken a day off work and spent teatime balancing boiled eggs on my knee and ringing local hospitals and the police to ask if any unidentified females had landed on their doorsteps.

Friday morning came. No Lisa. I took another day off work and phoned the hotel in Sussex to cancel our weekend. I began to feel inadequate. Why didn't I have her boyfriend's phone number? Why didn't I know how to reach her mother in Devon? Why wasn't she answering the phone? I put the baby to sleep and trawled through the telephone bills looking for a regular listing of a Devonshire number. No joy. When the baby woke I drove to her flat and rang the bell. No reply. I left a note.

In desperation I rang the long-established nanny agency which had given her name to us and supplied her (excellent) references. They offered to take over the search. The following few days were a nightmare. My stomach churned all day long and I couldn't sleep at night. Conflicting thoughts raced and clashed in my mind. I'd be frantic with worry one minute, hostile and angry the next. Why don't you get in touch, I screamed silently, while trying to explain her absence to my questioning daughter and plan for the next week's child care.

As the silence dragged on, I became more angry. I had invited her into our home, treated her as one of us and valued her because she was looking after our precious two children. I had asked about her social life, given her time off to see her family, shared the odd secret with her, yet now she felt like a complete stranger.

A few days later the nanny agency rang. They had tracked her down as she was moving out of her flat and a sad tale emerged. She was four months pregnant and her boyfriend didn't want to know. On top of all this, she was being evicted. She had walked out that Wednesday night, her mind a blur of worry.

She had spent her first two absent days at the local council trying to get rehoused. They said they could only do something if she was unemployed, then they could make a case for her to go into bed and breakfast. So she gave up her job without a word.

I had known nothing about her pregnancy or her troubles. I felt desperately sad that she had not asked me for help. Lisa had told the agency that she had liked her job and adored the children but she couldn't face the shame of telling us. I wouldn't have advised her to go into bed and breakfast, but then I probably would have suggested an abortion, which she wouldn't have wanted either. And if only she had phoned us, returned to say goodbye and allowed herself to be thanked for the time and care she had given the children. They, too, needed to say goodbye.

I was also struck by her determination to accept what seemed a grim fate. To me, set on a career and buoyed up with middle-class self-confidence, her decision to isolate herself, away from her family and in a big city, seemed tragic. In recent debates about single mothers I've heard many times that they don't intentionally sink themselves into poverty, but here was a council telling a girl to give up her job to be rehoused in a B&B.

Five weeks after Lisa disappeared, calm returned to our household. Our new nanny started and has been a great success. And Lisa? We have still had no word and our keys were returned in an envelope with no note. I had five uncomfortable weeks because of Lisa, but she and her unborn child face a much more difficult future. I wish her luck, wherever she is.