Are classes of 70 ever acceptable?

If I were Jim Knight, I don't think I'd have chosen a teaching union conference to share my enthusiasm for classes of 70 - even the supposedly progressive ATL. But does he have a point? First, despite credulous headlines in the Mail , let's be clear what Knight was talking about and what he was not talking about. The minister was not proposing that students spend all their time, or even the majority of it, in classes of 70. Nor was he suggesting that the Pupil Teacher Ratio - currently 16.5 in secondary schools and falling - should change (indeed there is now one adult to every 11.4 secondary pupils, much better than the 14.5 when Labour came to power). But he was recognising that some schools have experimented with such classes for particular lessons or lectures and that they have found them to work. I've seen them working extremely well (I'll spare the school concerned the attentions of silly reporters) and the challenge of a well-structured large mixed-age class can be particularly valuable for able students; there were a host of teaching assistants on hand to help those who needed it. Equally, a masterclass by a university lecturer or star speaker could be of such a size - or, as often happens, be provided across several settings using broadband. If we don't let schools experiment in such ways, not least with the chance for IT to offer each student different challenges, without being shouted down by teachers who should know better, go-ahead schools have no chance of finding the best ways to engage students in learning.