What you end up with, inevitably, is a group of children selected on the dubious basis of teachers' subjective judgements and parental pushiness. Like the current system of secondary school 'choice' (in practice, schools choosing the pupils they want, not vice versa), it looks open and equitable, but is in fact deeply divisive, favouring the precocious over the plodding, the already well-supported and resourced over those whose 'talents' are slow in developing or in need of nurture before they become apparent.
And once you've selected your elite group, you divert previous teacher time and resources to providing them with opportunities that reinforce their 'specialness' and are, inevitably, denied to those who didn't make the cut. One day last year, my teenage son came from school and told us there had been a special seminar on applying for Oxbridge. The trouble was, he didn't get invited, since (although he's bright and does well at school), it was only for members of the gifted and talented group, of which he's not a member. I was livid. Having been a shy, late-developing teenager myself, one who would never have been noticed by anyone drawing up a list of the 'gifted and talented', and coming from a family where no one had ever been to university, I would never have made it into higher education, let alone to the Cambridge college where I ended up, if this system had pertained in my day.
The diversion of money from this wrongheaded scheme into widening access to university is one of the Brown government's rare egalitarian moves, and almost (but not quite) makes up for Peter Mandelson's Gradgrindian comments on higher education last year.