When a Labour politician or aide stops to chat in the corridors of parliament these days, they only have one question: which leadership candidate would the Tories fear most?

The government majority of 80 means it would be hard for even the most talented Labour leader to land a House of Commons victory in the coming years, yet he or she would still have the potential to change the dynamic of this parliament — and disrupt the Tories’ hope for the 2024 election.