When whoever wins the Conservative leadership becomes prime minister on or around 23 July, the closest historical precedent for their situation might well be that of my personal hero, William Pitt the Younger, when he took office on December 19 1783.

He faced a country utterly fed up with politicians and a majority of the House of Commons determined to frustrate him. With little experience behind him – he was 24 – and leading a minority government, his prospects were regarded as near hopeless. The cynics were confident that it would be only “a mince-pie administration”, discarded by the end of Christmas.

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Yet it turned out that Pitt had been grossly underestimated. Because he knew what he wanted to do, he could pursue a clear strategy: break the deadlock in parliament by calling a general election as soon as he could build his popularity, but not waiting so long that he might become paralysed by the stalemate. After winning a landslide victory, he was in power for the following 17 years.

Naturally, there are many differences between the politics of 1783 and 2019. Pitt was installed in Downing Street by George III, not by party activists, and the cabinet he cobbled together was known for its collective capacity for port wine rather than youthful indulgence in drugs. But the parallel with today’s parliamentary deadlock is useful, because the lesson of his success is that a prime minister in such a dire position can only survive if he or she has a clear idea from their first moments of a plan to transform the situation.