broadcast anniversaries 25 February 1967: broadcast of third episode of The Moonbase . The Cybermen take over the base, but Polly works out a way of killing them with nail varnish remover. 25 February 1978: broadcast of fourth episode of The Invasion of Time . Leela and the Shobogans combine with the Doctor to destroy the Vardans; but the Sontarans have landed.