TODAY, the Queen will welcome the second British Prime Minister in succession to have initially entered Number Ten without the inconvenience of winning a general election.

Theresa May was installed three years ago by Tory acclamation. Boris Johnson is now taking over the reigns of power despite having been elected by 1/60th of the UK voting public. This surely isn’t sustainable.

There is nothing unconstitutional about this, of course. Under our parliamentary system of government, we elect parties to Westminster, not individuals. The winning party chooses its leader, and as long as they can command a majority in the House of Commons, they become Prime Minister. MPs could elect an empty chair, in theory at least, and stuff it in Number Ten.

However, we are in singular times, on the eve of Brexit, and with the country divided on its future as never before. It is very doubtful that Boris Johnson possesses a working majority in the Commons. Following the forthcoming Brecon and Radnorshire by-election, which looks likely to the first Liberal Democrat victory for their new leader Jo Swinson, the PM has a theoretical majority of two.

Mr Johnson’s coronation was accompanied by the pre-emptive resignations of key cabinet ministers, led by the Chancellor, Philip Hammond. The soon-to-be-ex-Development Secretary, Rory Stewart, is sounding more like a Liberal Democrat by the day. It will only take a couple of defections, and Boris Johnson is toast.

Labour will surely carry out its threat of a confidence motion against Mr Johnson’s plans for a No Deal Brexit. His election was carefully timed for the end of the parliamentary session to prevent any such motion before the summer recess. But Parliament resumes in September, and Labour will surely be ready. He could lose and become a footnote to history.

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Even if he survives a no-confidence motion, Boris Johnson still faces an impossible task. Parliament has made clear, not least in last week’s vote, that it will not allow itself to be “prorogued”, or shut down, to allow a crash-out Brexit. MPs almost certainly have the ability to prevent a No Deal happening, especially with the most activist Speaker, John Bercow, in the chair.

So, Boris Johnson should accept the inevitable. He should start preparing now for a general election in early October, before the Brexit deadline. Labour will have no choice but to support him. It’s a gamble, of course, and could be a disaster. But Boris Johnson is nothing if not a chancer. He has said himself that it is important, every so often, to “blow yourself up”, metaphorically speaking, in order to move on.

With Jo Swinson in her honeymoon phase, polling neck and neck with Nigel Farage’s Brexit Party, this might seem like precisely the wrong time for an election. Mr Johnson said yesterday his strategy is “DUD”: Deliver Brexit, Unite the country, then Defeat Corbyn. But he must know the chances of his surviving that long are, well, dud. He could go to the country early claiming a Remain parliament is defying the will of the people, that his hands have been tied by MPs determined to block a No Deal Brexit. Naked in the negotiating chamber, if you can handle that image.

An early election would immediately remove the threat from the Brexit Party. Nigel Farage has no credible policy programme or manifesto to offer in an election precisely because Mr Johnson is seeking a mandate for a “do or die” No Deal Brexit. Mr Farage is a single issue politician, and his issue has been stolen from him. Most Brexit supporters would switch back to the Tories, giving Mr Johnson a big poll boost in the run-up to the election.

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As for Labour – they still don’t have a coherent policy on Brexit and are mired in a bitter civil war over anti-Semitism. Most of Labour’s 40 or so target seats are in pro-Leave constituencies. So even if Jeremy Corbyn gets off the fence and calls for a People’s Vote the Tories could still prevail.

Too many of Labour’s supporters and some commentators have persuaded themselves Mr Johnson is a “racist”, a “homophobe” and even a “neo-fascist”. He is none of these things, as anyone who knows him will tell you. He had good relations with the Muslim community in London when he was mayor. He led Pride marches, even wearing a pink stetson. These are not the actions of a white supremacist.

The opposition parties need to attack the real Boris Johnson, a liberal Tory populist, not their cartoon image of him as a blond Nick Griffin. Otherwise the attempt to portray him as far-right extremist will backfire. He will make speeches praising diversity and well-funded public services. He will appoint a number of non-white advisers, like Munira Mizra, his cultural adviser in London, who is expected to have a leading policy role. Labour could be in for a shock when they find out how popular Boris Johnson is, in England at least.

But not for viewers in Scotland. The SNP will get a significant boost from the new Prime Minister, or “Minister for the Union” as he calls himself. He will be coming to Scotland within the next week, no doubt waving the odd Arbroath Smokie and claiming that the Scottish fishing industry will boom after Brexit.

But no Conservative politician since Margaret Thatcher has had such a consistently negative image in Scotland. The Scottish Secretary, David Mundell, said he could never see himself serving under Mr Johnson, and the leader of the Scottish Tories, Ruth Davidson, actively campaigned against him. Boris Johnson could kill the Scottish Tory revival stone dead.

On current polling, the SNP should be in line for 40-45 MPs. The UK Lib Dems are unlikely to win many more since their votes are spread thinly across the country. A Labour/SNP/Liberal coalition is a theoretical possibility, but unlikely. There would be resignations from Labour if Mr Corbyn agreed to a Scottish independence referendum. And the Lib Dems are bitterly opposed to the SNP and Corbyn.

So Mr Johnson has nothing to lose. It can’t go on like this. There must be a general election before Brexit to judge the mood of the nation. It’s time for this newly unelected Prime Minister to say: “back me or sack me”.