As a teenage single mother and civil war refugee from Somalia, Naima Sharifdahir appeared to be doomed to academic failure.

Yet the teenager, who arrived in Britain five years ago speaking little English, achieved impressive GCSE results and now intends to become a doctor.

It was not her background or personal circumstances that held her back initially, but the disruptive behaviour and low expectations at the inner-city comprehensive that she attended. Naima, 18, said she was horrified by her classmates' attitudes at South Camden Community School in Central London and the lack of ambition that teachers had for the pupils.

“There was no focus on education,” she said. “I was used to home tutoring. Then I came to England and joined a class of more than 20 pupils trying to annoy the teacher.

“They had no respect for the teacher, who would often leave the classroom in tears. It upset and demotivated me. These students were messing it up for everyone else.

“I didn't know anything about the GCSE system when I started, and by the time I realised what was going on it was too late to do well at that school.

“The teachers would say to pupils, 'Don't try to do that, it might be too hard. Don't worry, you can get a C grade without it'.”

Naima speaks with confidence and determination. A Muslim, she wears long skirts and covers her hair when outdoors but eschews the veil and has brightly painted nails. She bounced her year-old son, Yonis, on her lap as she talked.

Her achievements confound statistics. Recent research indicated that Somali children are among the lowest achievers at school. Only a third of Somali pupils in London got five GCSEs at grade C or better last year.

Added to that is the low expectation of teenage mothers, many of whom drop out of education when they become pregnant.

Naima married at 16 but is now raising her son alone. She left school without sitting her GCSEs but read widely to improve her English.

Her tenacity and resolve then came to the fore: she overcame assumptions about young mothers by enrolling at City of Westminster College last year, when her son was two months old.

She was accepted despite eyebrows being raised when she arrived for an interview with her son.

She said: “The lady on reception just looked at me and said, 'I'm not sure they'll take you. It will be hard for you, having a child'.

“I promised I would keep up my studies and then I met my tutor who was really supportive. But she made me promise to turn up early for all my classes. There's a presumption that if you have a baby young your life is over. People asked how I was going to cope. They'd give this smile as if they thought I was dreaming.”

Naima studied for ten months, while bringing up Yonis in a council flat, before taking six GCSEs and achieving five As and a B. Today she starts A levels in chemistry, biology, maths and psychology.

While thousands of middle-class teenagers celebrated similar grades with lavish parties, or by spending money given to them as a reward for good results, Naima had a meal at her parents' house before returning to her one-bedroom flat in Somers Town, a rundown area between King's Cross and Euston stations.

She credits her parents' love and support for allowing her to pursue her ambitions: “My mother and father tried to drum into all their children's heads the importance of education. I'll always be grateful.

“They said it would be best if I went back to college so I could create a really bright future for my son and myself. My mother looked after my son while I studied, and I took over when I came home.”

She adds: “Faith is very important to me. When I realised things were falling apart it was what held me together. My religion says you should be determined and work hard, so I did.”

Naima has wanted to become a doctor since she was a child, helping to look after her younger brothers and sisters. The family left Somalia when she was six because of the civil war and moved to Kenya, before migrating to Britain seven years later.

She says her country's war is heartbreaking, adding: “It can be painful seeing people from the same country being cruel towards each other because of tribal issues. Now Britain is the closest thing I have to home.”

Times recommends

• Screen tests are the future of exams
• No more free boarding schools for diplomats
• Popular Jewish School broke race laws