I go every year and have seen it grow from a small one day ecvent to a huge week long event with part of it being academic study in the preceding week followed by the festival over the weekend. Always full of a good range of acts from a variety of genres. If you go come to the NASUWT stand and say hello.
Leadfingers - it's now run by S W TUC and the format has changed considerably. Nigel Costly is the guy who does the bookings and he books 2 years ahead now.