Best delivery is TV history there.
Jokes aside, I do tend to enjoy hammy acting, and this is the episode where Barbara as Jadis got the reputation of overdoing this role. The HOW DARE YOU is said all over our house.
Aside from that line, this is my favorite of the first three episodes, even though it's the least popular. And for good reason, as the beaver costumes are frankly terrible, and the episode is rather slow. However, the story really picks up here, and Mr Beaver is a favorite character of mine for some reason, despite the hairy egg that is his costume. The set for Jadis's castle is great, and Maugrim was well acted despite a not-as-bad but still pretty bad costume. The interior and exterior, with the statues and walls, give a great Narnia vibe. The scenes with the beavers are nice and homely and give a nice idea of life in Narnia. Also, I love the beavers house.
I rate this 86% into Tier 4 (Pretty Good).