Number 10:
Invasion (of the Dinosaurs) 1974
A classic "they turn up and everything is wrong" episode. It has a really creepy atmosphere, you just feel it's not quite right as soon as the episode starts. A classic deserted London ala The Dalek Invasion of Earth. Nicely done.
Lots of Doctor and Sarah scenes too. I love the way they're thrown up against bureaucracy and they can't escape it. No-one will listen, no-one cares. It feels more threatening than an army of Axons. Great stuff- very Malcolm Hulke isn't it? He loves this stuff and does it very well.
The dinos themselves aren't great, but they do. The pterodactyl is the better of the two we see, Kklaking at pertwee as he tries to start the land rover in the warehouse.