Selection is a taboo word in the Labour Party. So much so that, in his five-year plan for schools unveiled last week, the Prime Minister explicitly forbade schools to select their pupils. But he wants to free the best schools from local authority control, allowing them to set their own wages and curricula and giving them the chance to expand. As this means that popular schools will be oversubscribed, surely they will be forced to select their pupils?

Once, like many of my Left-wing teacher colleagues, I would have been enraged by the idea of selection. However, my experience as an English teacher in London comprehensives and the example of a naughty 12-year-old boy called Rees have taught me to welcome it.

Two years ago, I started teaching at The Coopers’ Company and Coborn School, which is nominally a "comprehensive". Set up by a livery company during the reign of Henry VIII, it still caters for children from all over east London. Much like the London Oratory, where Tony Blair sends his children, its "faith school" status allows it to interview children and pick bright, articulate students – whatever their background.

Rees was one of our chosen. He was very much an East End lad: highly intelligent and streetwise. He lived with his mother in a tower block and I knew the school he would have gone to if he hadn’t come to ours. Many of the children there were unable to read and write fluently and a hard-core would be thoroughly disruptive. In such places it is simply not "cool" to be academic; so many of the students just refuse to learn. Indeed, some are often bullied if they work hard, so the few cleverer children are dragged down.

At Coopers, however, most pupils want to work hard. And when he got here, so did Rees. Seeing him tackling ambitious subjects and clearly benefiting from the experience, changed my mind about selection.

I can hear protests of the cossetted educationalists: "Ah, but what about the schools in his area that are deprived of pupils like Rees by selective schools?" But in my experience it is the disaffected, clever children who are by far the worst behaved. They have too little to do; they have time to be disruptive. And Rees was indeed a badly-behaved boy. When I first taught him, he liked to flick rubber bands and attack some of his school mates if he was not fully engaged.

In an typical comprehensive he would have probably become a serious threat to discipline, but he didn’t with us because he soon found himself challenged by his work. I saw a miraculous change come over him as he progressed. He became competitive about his work when he saw that other boys – tough characters like himself – wanted to do well. Because the standard was higher than in his previous school he had to fight harder and much of his energy was diverted and absorbed in trying to succeed.

New legislation coming into effect in September means that our school will no longer be allowed to choose students by interview. I dearly hope that Labour’s five-year plan which will form part of its election manifesto can make the further change which allows us to select again.

A decent education should not be a middle-class perk. The failure of state schools has had a terrible effect upon our society, which remains as divided as it was 30 years ago, if not more so. I still can’t see many working-class children reaching the top of the media, the legal profession, the universities, medicine or politics. The two men in charge of education in this country, Tony Blair and Charles Clarke, are from public schools. Let us hope that, if they are elected again, they will allow schools to select their pupils and give other children like Rees the chance that they had.