- You may be looking for Ted Heath.
Heath was the party leader in 1965. Toby Kinsella remarked that he would never adopt the Sunday Club's policies, to which William Heaton MP said Heath wasn't going to win the next election. (AUDIO: Changing of the Guard)
As it turned out, Heath did indeed succeed Harold Wilson as the Prime Minister of the United Kingdom after the latter's June 1970 re-election bid ended in failure. Part of the cause was a series of scientific disasters (which the public was unaware were down to aliens). These continued under Heath, undermining him. (PROSE: Who Killed Kennedy)
In 1974, several children were surprised to see Harold Wilson and not Heath attending a Ministry of Defence briefing. Emilie explained, "It's Mr Wilson's turn [as PM] this month." (PROSE: Daleks: The Secret Invasion)
Behind the scenes
1974 had two extremely close and messy general elections. Both The Green Death and Secret Invasion are making fun of the elections: The Green Death by joking that the small Liberal Party is going to end up winning, and Secret Invasion joking that Wilson might not last very long.