Deborah Gearing gave up teaching after a year. She felt listening to children's problems was more important than teaching them.
The 46-year-old playwright trained as a languages teacher. But she was more interested in helping vulnerable pupils than in educating them.
"I didn't have time to talk to the kids who needed talking to," she said.
"I was happy not to teach, just to listen.
"Their problems were so much more important than, say, learning German.
When a child told me his problems, and then asked, 'why do I have to learn this?' I'd say, 'I don't know'. I wasn't a terrific teacher."
Now Ms Gearing, who has written plays for regional repertory theatre, has decided that she can help pupils better by focusing on drama.
Her latest play, Burn, written for the National Theatre's annual Shell Connections festival, explores the vulnerability of looked-after children.
Throughout this month, secondary pupils participating in the festival will perform new material, custom-written by three professional playwrights, to paying audiences at the National Theatre. Burn is being performed alongside plays by Mark Ravenhill and Enda Walsh.
Burn tells the story of a teenage loner in foster care. While not based on any one individual, the story was inspired by a theatre group of looked-after children whom Ms Gearing had worked with.
One of the teenagers in the group was forced to drop out, when she was transferred to a foster home across the country.
Similarly, Birdman, the hero of the play, is sent against his will to a foster placement in Birmingham.
"I had been very naive," Ms Gearing said.
"I knew there weren't enough foster families to go around. But I didn't understand what that meant: being uprooted, being moved away from friends and family, the discontinuity.
"As a looked-after kid, you can feel invisible. I hope that some kids will identify with what I write, and feel validated by it."
And she believes that theatre projects, such as Shell Connections, are particularly beneficial for looked-after children. "I believe in the healing power of drama," she said.
"It gives you an opportunity to be part of a group, part of a community, working to a shared end. It's not about passing time. It's about community endeavour."
"And it's about play. So many of these kids haven't had much time to be carefree and play as children should. We need to give them time to recover that."
Burn opens on March 15.See www.shellconnections.org