score:2
Alan Bennett was interviewed about the play The History Boys by the Telegraph. In the interview he was asked explicitly about that phrase. He replied:
The phrase actually comes from George Steiner – I asked his permission to use it – and it comes from his latest book called Lessons of the Masters. Steiner talks about the whole question of sexuality and teaching, and though I'd written the play before I'd read it I was heartened that some of the things – for instance the notion that Irwin's teaching is sexualised by the pupil who actually takes it all on board – wasn't just an idea I'd had, but can occur as part of the nature of teaching.
As far as I can see, Bennett seems to have paraphrased from Steiner, rather than quoting verbatim.