Had Floella Benjamin not changed her accent, and quickly, she might have ended up in a class for children with special needs.

The 55-year-old writer and broadcaster said her mother told her to conform at school, however bad she was made to feel for being black and different.

Ms Benjamin, who arrived in London in 1960 aged 10, was amazed to find that while she knew all about England, her new classmates knew nothing about her homeland, Trinidad.

She said: “A teacher called me a guttersnipe for speaking with a Caribbean accent. I felt I had been stripped of my dignity.

“But my mother pointed out that if my teachers didn’t understand me then I would be the loser. If I had not had such wise parents I would have ended up in the class for pupils with learning difficulties.

“I learned very quickly I would have to fit in. You cannot always fight, you have to take what is on offer and use it to your best advantage.”

She was speaking as Ken Livingstone, the London mayor, launched a campaign to halt underachievement by black pupils, especially boys, in the capital.

But unlike Ms Benjamin’s mother, it will not be asking black children to conform. Instead, measures are being put in place to halt the spiral of underachievement through the recruitment of more black teachers.

Golden handshakes and fast-track teacher training are to be offered to black people to encourage them to act as role models.

Mr Livingstone said that up to 20 per cent of the workforce needed to come from ethnic minorities to improve standards and reflect the population of the capital.

His comments came as a 250-page report looking into the poor performance of black African and African-Caribbean youngsters, particularly boys, was published.

Entitled Rampton Revisited - the Educational Experiences and Achievements of Black Boys in London Schools 2000-2003 the report will form the backdrop for tomorrow’s third Londonwide conference into the performance of black children.

Mr Livingstone refused to be drawn on a timescale for implementation of the proposals or the value of financial inducements, but said a dialogue was needed with all interested parties on the way forward.

“I hope no one will pull up the drawbridge,” he said. “We cannot waste time as too many generations of young black Londoners have already been failed by the system.”

The report, by the London Development Agency, is the most comprehensive on the performance of black boys in London’s schools.

It shows that at key stage 3, 46 per cent of black Caribbean boys achieved level 5 or above in English, compared with 62 per cent on average for all ethnic groups.

At GCSE only 25.1 per cent gained five or more top grades, compared with 46.2 per cent of white children and 60.3 per cent of Indians, who were the highest achievers.

Low teacher expectations and inadequate attention were a factor, as were unfair behaviour management and an inappropriate curriculum.

The Teacher Training Agency said it was committed to increasing the number of black teacher trainees and the Governmentsaid it was working with parents and targeting schools to raise achievement.

But black boys told researchers that once they developed a reputation it was hard to shake it off, even if they made a concerted effort to improve.

They also complained of being viewed with suspicion or subjected to negative stereotyping.

“When it’s white boys it’s a group but when it’s black boys it’s a gang and I think that’s wrong,” said one.