One of the only episodes of Blake's 7 I really remember is "Orbit", in which Avon and Vila play a game of cat-and-mouse aboard a shuttle that's been stripped back to the wiring but is still doomed to crash into the planet it's trying to launch from unless another 70 kg can be ejected: as Orac helpfully points out to Avon, this is more or less exactly Vila's body mass. The respective faces pulled by Avon and Vila as Orac announces this tell you everything you need to know about their characters.