The Avengers - A Sense of History
As for the episode itself, it's a mixed bag. The background is surprisingly serious, a violent and indeed murderous clash of political ideologies at a university. The execution is rather silly, but sort of fun.
I'm not quite sure how Robin Hood got to pay such an important role in this episode but it did offer Diana Rigg the opportunity to wear a truly astonishing Robin Hood costume. It's revealing enough when seen from the front; when seen from the rear it leaves very little to the imagination.
Patrick Mower does what he was good at, adding a genuine sense of menace, and there's much silliness with swords and bows and arrows.