This episode was written by McGoohan, and is suitably odd. The Prisoner is invited to participate in an election campaign. He is offered the chance to be the New Number 2 if he can beat the current incumbent.
No. 6 thinks this is unlikely but he gives it a go anyway. The whole election is blatantly rigged, but to make The Prisoner win! He is also subjected to brainwashing to make him carry on when he realises the whole thing is a sham and quits. The whole episode is grim parody of democracy.
There's also a violent scene near the end that was cut on initial and subsequent transmissions.
Here's a clip, the Prisoner here has been hypnotized and brainwashed before this scene, a comment perhaps on politicians spouting insincere rhetoric.
