Theresa May has a thumping 33 point lead over Jeremy Corbyn in the latest opinion poll – bigger even than her Party’s one over Labour, which itself is the largest for seven years.  The Conservatives were not defeated last week in Richmond Park, since Zac Goldsmith stood as an independent.  And they have just gained their best by-election result since the Falklands War at Sleaford and North Hykeham.  In short, May faces the weakest opposition since the Michael Foot years, perhaps since the Second World War.  That she has replaced a Tory leader in this Parliament provides a powerful reason, were others lacking, for her to stay in place until the 2020 election and perhaps well beyond.  Furthermore, she has no obvious successor who commands support among Conservative MPs and party members. All this helps to explain why this site has suspended one of its regular features: our next Conservative leader survey.

Which brings us to Boris Johnson.  May seems to have wanted a Brexiteer to lead the Foreign Office – and one, furthermore, who has the intellectual curiosity, oomph and star quality to give it a new sense of purpose after the collapse of its credo last June: that Britain’s place is in the EU.  That meant sending for the former London Mayor.  But theirs is not an easy relationship.  She is a roundhead; he is a cavalier.  She is Prime Minister; he thinks – it is fair to say – that he should be.  Above all, she likes to control everything; he hates to be controlled.  Leave aside for a moment the row over what he said about Saudi Arabia, and look back just a little bit further to last weekend.  The Foreign Secretary said during the course of an interview on The Andrew Marr Show that students should be taken out of the immigration figures.  It was then only the latest instance in a long history of Johnson freewheeling out loud – and, now that he is a senior Minister, freelancing to boot.

Blame him, if you like, for failing to play by the rules, act collegiately, grow up and, above all, become the serious statesman that his country needs at a time of instability abroad.  Or blame her – and some of his Cabinet colleagues – for mocking him to his face, allowing briefing against him behind his back, and now sending out her spokesman to humiliate him publicly.  Either way, there is a twin lesson to be learned from this week’s events, assuming that they are not to be dismissed as a storm in a Westminster teacup, rather than diagnosed as an open wound that risks infection.  First, Prime Ministers are, as is sometimes said of Russia, seldom as strong as they look and seldom as weak as they look.  For all May’s command of the domestic landscape, she cannot easily fire or demote a senior Brexiteer – let alone the one Conservative campaigner who can reach voters that others can’t reach.  She will have seen his powers at work as recently as last June.

Downing Street will have noted that the Foreign Secretary’s friends at Westminster and in the media are out and about, joining with critics of the Saudis to applaud what he said, criticise the Prime Minister’s handling of him, or both.  No other leading Tory has that kind of backing.  Which leads to the second point.  Johnson campaigned for Brexit; she must now deliver it.  They therefore need each other, and badly.  Perhaps neither of them think so: he because he hankers after a kind of Vote Leave  Government, led presumably by the star of that organisation’s referendum campaign; she because she believes that, ultimately, her administration can carry on without him.  It doubtless could.  None the less, George Osborne and Michael Gove are already stalking the backbenches; to send Johnson there too could create one problem too many.  But whether so or not, what matters most is not the Conservative Party’s internal complications but its public duty: to deliver an orderly Brexit.  This falling-out is doing it no good, and is in danger of creating its own momentum.