It has to be said that state secondary schools are not renowned for oiling the wheels of social mobility. You start school as a taxi driver's daughter, then you leave and marry into the mini-cab classes. Proudly egalitarian our schools may be, but their heterogeneous nature fosters downward rather than upward mobility. You see it with each new Year 7 intake: little Daisy comes in wearing boxed pleats and talking like Mary Poppins; two years later, she is wearing more make-up than clothes and sounds just like Cheryl Kurrrl. To be fair, not even Julie Andrews could withstand the peer pressure of our militant Year 9 posse: before long she would be effin' and meffin' with the best of them while shoplifting some of Claire's more accessible accessories.
Teachers who put their own kids through the state-school system are more aware of the dangers than most. It is a bit like chucking your delicates into a mixed wash. You know you are running the risk that those bottle- green towels will bleed into your Bravissimo smalls, but you do it anyway because it is morally right, you have firm principles and, besides, you've run out of powder. Anyway, there is always an antidote. As long as your kids don't mess up their A-levels, you can rely on Vanish Uni Action to absorb the toughest vernacular stains.
Once you have got them to university, the massive gravitational pull of the middle classes draws them away from any residual proletarian influences. The first thing to go is their accents, followed by their love of oven chips. Eventually, like my eldest, they arrive home clutching "internships" along with a pile of dirty washing. I would sooner he had brought Black Magic, but beggars can't be choosers. The fact that he has got an "internship" and not "work experience" is testament to his new social mobility. He is a traveller in a foreign land whose inhabitants buy hand-pleated curtains and select wines by the region, not the grape. He managed to secure his internships thanks to a considerate university colleague, but at the cost of his usual summer job selling shoes. In this brave new world, fagging for a barrister is a more esteemed skill than fitting T-bar sandals, although it offers less money and fewer shoe care perks.
Internships make me uneasy because, as Nick Clegg pointed out, they are predicated on privilege and string-pulling ability. If you have lent an Old Etonian a cup of sugar, your kids might get a couple of weeks in the Cabinet, but if your social network is limited to people in high-vis jackets, your connectivity will be as useful as O2 on a foggy day in Cumbria.
But reassuringly, it is not just the working classes who need the occasional leg-up. A colleague is tutoring some private-school kids who have not made their grades. The fact that they need a state-school teacher to top up their expensive education raises a question mark over the robustness of the original purchase: a bit like paying for a Michelin- starred lunch then buying a pasty to go. But my friend reckons it is not just her pedagogical skills the parents are after. Given she is a gritty Yorkshire lass, she thinks they see her as a form of "healthy bacteria"; a human vaccine immunising their kids against contamination should they end up at their insurance-choice university.
Presumably, exposure to her not only improves their coursework grades but also protects them against wearing Primark, voting Labour or developing a Tango-orange tan.
Anne Thrope (Ms) is a secondary teacher in the North of England. She was highly commended in the Business Columnist of the Year category in the 2011 PPA awards last week.