The government's hike in tuition fees is a genuine revolution. It changes the rules of the higher education game for universities, students and the government and many of the consequences are unknowable. In particular, we don't know how students from poor families will respond. Will many of them, as critics fear, decide not to go to university? This is one of the gambles ministers are taking and potentially the most politically toxic element of the new policy. If, come the next election, voters believe poor students are turning away from uni then tuition fees will continue to hang round Nick Clegg's neck like a burning tyre. Hence the government is moving now to defuse the electoral timebomb. This is what lies behind Clegg's media work on fees this week and the letter going today from ministers to the Office for Fair Access.