The only person who can prevent Boris Johnson from becoming Britain's next prime minister is Boris Johnson, and he is trying his best to do just that.

In reality, the former mayor of London so personifies the hopes of Brexit Delivered in the minds of his Conservative Party members that even he couldn't stand in his own way now. And yet his campaign - in which his trustworthiness and grasp of the issues are being called into question - may be making what will be a difficult job impossible.