Physics teacher Martin Bendall is just the kind of super-teacher Martin Stephen (see opposite) wants teaching only the brightest students.
He has a 2:1 degree in physics from Imperial college in London, but he strongly disagrees with Dr Stephen.
Mr Bendall is head of science at one of the country's top comprehensives, Dixons city technology college in Bradford. He said: "Just because you go to Oxford or Cambridge and you come out with a first it doesn't mean you're a good teacher.
"It doesn't take into account the professional skills: some of the best teachers wouldn't have a first in science or any subject."
Other high-flying teachers said working only with bright pupils could be unrewarding.
Kath Viala, a graduate of St Anne's college, Oxford, taught at a grammar school before becoming head of history at Copthall, a girls' comprehensive in north London. She said: "There was no challenge at the grammar school.
You felt you could put a donkey in front of the kids and they could still get As."
Andy Christy, a maths teacher at St Aidan's school in Harrogate, north Yorkshire, left university with a first in maths and statistics and taught for two years at an inner-city school in Newcastle.
He said: "It was very low ability with huge discipline problems, but I look back on it very fondly. Having taught students at that level, I feel I have become a much better teacher."
Trevor Millum, head of the London Association of English, said: "I've got a PhD in English. I have found you need all your quick-wittedness and intelligence to teach the less able."
Teachers with average academic qualifications were angered by Dr Stephen's views.
Simon Rockett, physics teacher at Debenham CofE high school in Stowmarket, Suffolk, said: "I think that's insulting. I have a 2:2 degree, does that mean I am not entitled to teach bright children?"
Gary Longman, head of the King's School in Peterborough, Cambridgeshire, says teaching is about personality. "You need to be able to raise enthusiasm among your students. You certainly don't achieve personality by taking some exams."
David Reynolds, professor of education at Exeter University, said: "This is a very silly suggestion. Historically, 20 or 30 years ago, the best teachers educated the brightest pupils. Everyone knows that made the age-old problem of British education worse: that is, the creation and education of an elite. In my experience, schools were making tremendous efforts to spread the best teachers through the ability range. Now someone comes in and says they shouldn't be doing it. I think it's a very inept intervention."
But Margaret Brown, professor of maths education at King's College, London, and a member of Labour's numeracy taskforce, said schools may have to follow Dr Stephen's suggestion out of necessity.
She said: "Where there is a shortage of maths and physics teachers, perhaps it would be better for higher qualified teachers to teach the more able.
"I find it very difficult to say that. However, you may have a situation where you can't have both and therefore you have to tailor it to what you've got."