Teacher Clare Morrall was in the middle of a piano lesson with nine-year-old Angus McDonnell when she heard her novel had been shortlisted for the Man Booker prize.

“Congratulations,” he said. Then they carried on with the remaining half-hour of the lesson.

“Angus was very sweet,” said Mrs Morrall, 51, who teaches piano, violin and music theory at Blue Coat preparatory school in Birmingham. “I had said I might get a phone call about the book, he said ‘let’s hope you get on the shortlist’.”

Her book Astonishing Splashes of Colour is the story of Kitty Wellington, who sees emotions as colours and is struggling to accept the death of her baby son.

It is her fifth novel - the previous four are unpublished - and it was rejected by 33 agents before being taken on by the tiny Birmingham-based-publishers Tindal Street Press. “I was thrilled when it was published,” said Mrs Morrall.

Now her book will compete for the pound;50,000 prize with Brick Lane by Monica Ali, the latest publishing wunderkind, Vernon God Little by DBC Pierre, Oryx and Crake by Margaret Atwood, Notes on a Scandal by Zo Heller (about a doomed teacher-pupil relationship) and The Good Doctor by Damon Galgut.

Mrs Morrall, who is self-employed, has been teaching and writing novels for about 20 years. She wrote her book in free periods between lessons and at weekends.

“I did try writing in the music room at school, but you get distracted because there are other things that need doing,” she said.

“Then one of the mums offered me a room in her house nearby so I could write there. I’ve been going there for about four years.”

Mrs Morrall was born in Exeter and moved to Birmingham to do a music degree. She began teaching individual children and gradually gave more lessons at Blue Coat school. She has a son, aged 25, and a daughter, aged 23.

“I gain a lot of insight through teaching, about children and adults motives, the way they do things,” said Mrs Morrall.

“I don’t think I’d like to give it up, although I do get very tired. I’m very fond of the children I teach and it keeps me in contact with the real world, which is not a bad thing.”

Astonishing Splashes of Colour

At 3.15 every weekday afternoon, I become anonymous in a crowd of parents and child-minders congregating outside the school gates. To me, waiting for children to come out of school is a quintessential act of motherhood. I see the mums - and the occasional dads - as yellow people. Yellow as the sun, a daffodil, the submarine. But why do we teach children to paint the sun yellow? It’s a deception. The sun is white-hot, brilliant, impossible to see with the naked eye, so why do we confuse brightness with yellow?

The people outside the school gates are yellow because of their optimism.

There’s a picture in my mind of morning in a kitchen, the sun shining past yellow gingham curtains on to a wooden table, where the children sit and eat breakfast. Their arms are firm and round, their hair still tangled from sleep. They eat Coco Pops, drink milk and ask for chocolate biscuits in their lunchboxes. It’s the morning of their lives, and their mums are reliving that morning with them.

After six weeks of waiting, I’m beginning to recognise individuals, to separate them from the all-embracing yellow mass. They smile with recognition when I arrive now and nearly include me in their conversations.

I don’t say anything, but I like to listen.