By securing 66.4 per cent of the vote, Mr Johnson will argue that the scale of his victory over Jeremy Hunt gives him a mandate to appoint his cabinet and pursue his new Brexit deal.
A mandate to become Conservative Party leader, however, does not translate into a mandate to govern. While he may have won the Tory leadership contest by two votes to one, the Conservative’s majority in the Commons is only two. It means that despite the scale of his victory in the Tory leadership contest, his reshuffle will be a delicate balance.
If he lines his cabinet with Brexiteer allies he risks fuelling the “rebel alliance”, led by Philip Hammond and David Gauke, of MPs implacably opposed to no-deal on the back benches.
Pro-European backbenchers believe as many as 20 Tory MPs could vote to bring down Mr Johnson’s government if he attempts to force Britain to leave the European Union without a deal. In his speech, Mr Johnson thanked members of the Conservative Party directly for their support. He said that while some will “question the wisdom” of his appointment as prime minister, he has faith in Conservative Party members to make the right decision.
Within minutes of the vote, Mr Johnson’s allies including Priti Patel, who is expected to secure a prime role in his cabinet, were hammering home the message that he has a mandate to deliver Brexit.
However, the parliamentary arithmetic is unsustainable. He will have no choice but to hold a general election within a year — either before or after Britain has left the European Union. Sooner or later, he will need a mandate from the wider electorate. Someone may want to warn Brenda from Bristol.