So. What Did We Learn from The Debate?

Primarily of course, we have learned that there are unlikely to be any more such debates as 'sacred cows' can so easily be slaughtered. The liberal left wouldn't have liked this at all. It simply will not do!
What case is there now for Our Nige being excluded from the leaders' debate before the General Election?
Clegg allowed in - Farage not? - Risible.
It's a UKIP vote-winner either way!