Today we are promised (yet another) review of university tuition fees. Yesterday the Treasury select committee launched its own report on student loans. As a cross-party committee, it shies away from the high politics, but it still makes important recommendations, including reducing the interest rates charged on loans and looking again at the funding of part-time degrees after a collapse in the number of part-time students.

The most interesting part of the report, though, explores the weird and wonderful world of government accounting for student loans. Believe me, this really is fascinating and important stuff. In fact, it is genuinely bizarre. And it may well explain more of current policy than is sensible. So please bear with me.

The first thing you need to understand