Tory faithful are male and grey but choice of leader is less clear cut

Tory delegates await Boris Johnson's keynote speech at the Conservative party conference in Manchester last October. Photograph: Peter Byrne/PA

The final decision on the next Tory leader ultimately falls to the party membership, after MPs vote to narrow the candidates down to two.

This means the decision on the identity of Britain’s future prime minister will be voted on by 200,000 people, more or less. And they are not just ordinary members of the public, they are fee-paying members of the party’s grassroots with their own sets of beliefs.