Ability used to be the principal requirement in a minister. But, post-Brexit, this, like so much else, has changed. Now the key, as the Financial Times editor Lionel Barber observes, is being able to keep whistling as the ship of state goes down.

“Everyone in the cabinet is being measured by whether they are cheery or miserable rather than whether they are competent!” Barber tweeted early on Monday morning. Rather than try to avert or mitigate the impending disaster, he argued, the officers on the Titanic are being judged – on the Brexit side at least – by the good humour with which they meet their fate.

Lionel Barber (@lionelbarber) Yes, and everyone in the Cabinet is being measured by whether they are cheery or miserable rather than whether they are competent! https://t.co/XjB91aVPpR

Brexiteers counter that Barber, as the representative of cautious business interests, would say that. Boris Johnson, ever cheery in his absurd shorts, attacked the FT in his conference speech last week, referring to it as a “distinguished pink newspaper [that] manages to make Eeyore look positively exuberant”. For good measure, he added that the Economist – which takes a dangerously reality-based view of Brexit – was “suspiciously unread”.

A reshuffle beckons. The Eeyores must all go – Hammond, Amber Rudd, those old bores Damian Green and Michael Fallon

Johnson (or can I call him Boris in this comedian-in-chief context?) is there to keep up the flagging spirits of the Tory party. At a conference that made most funerals look riotously joyous affairs, he managed to raise a few cheers with his usual stream-of-consciousness narrative, interspersed by the odd long word and Latin epithet. In a world of Bill Cashes and Bernard Jenkins, Johnson is Cicero.

But he is also, allegedly, foreign secretary, and on the whole foreign secretaries have been serious figures. OK, one could have spent a marvellously entertaining couple of hours with Charles James Fox (no relation of Liam), who was foreign secretary three times in the late 18th and early 19th centuries, but his stints were brief and he usually assumed office in rocky circumstances.

Generally, though, foreign secretaries have not been a barrel of laughs. Lord Castlereagh held the post from 1812 to 1822, and oversaw the negotiations that followed the Napoleonic war – a settlement similar in complexity to our current pas de deux with the EU. He did a pretty good job in the negotiations, but was widely despised for propping up repressive governments at home and abroad. “I met Murder on the way/ He had a mask like Castlereagh,” wrote Shelley. Byron was even ruder. But at least Castlereagh took the job seriously.

Wellington, the Earl of Aberdeen, Palmerston, Lord John Russell, Arthur Balfour, Ernest Bevin, Robin Cook, Margaret Beckett – all held the post without feeling the need to jog in swimming trunks, hang suspended from zip wires or make tasteless remarks about black people. They were committed politicians doing their best for Britain, rather than indulging their own egos.

But Brexit has made fools of us all. With the government directionless, the economy stalled and the future grim, the Tory press and the party’s backbenchers just want jokers now. It’s time for the House of Commons to install a vat of gunk, so that dull speakers can be tipped in when they fail to entertain. Or perhaps backbenchers should have buzzers so they can respond to hesitation, repetition and deviation. We want jokesters not policy-makers. This is no time for a dull old stick like Gladstone or Peel, with their high-falutin’ principles, labyrinthine arguments and party-destroying soul-searching. Bring on the empty horses.

Soon the country has to go over the top, and as we enter no man’s land, the Brexit brigade want us to be singing It’s a Long Way to Tipperary rather than questioning whether this is a war that we ought to be fighting in the first place. A second referendum, a quick renegotiation with the EU so we can tighten up on freedom of movement (plenty of rules on registration and benefits already exist), a continuation of our current highly advantageous trading conditions – no, let’s forget all that and go to our doom singing a merry tune. Nihilism is such fun.

In this prevailing mood, the Brexiteers are gunning for the chancellor, Philip Hammond – another reality-based Eeyore who is decidedly off-message in wanting boring things such as transition periods and protection for the City of London. Who needs the City, who needs tax revenues, who needs jobs, who needs economic growth or political stability? They are all so boring. Come on in, the revolutionary water is lovely.

Oddly, Brexit is the brainchild of the Conservative and Unionist party. They ceased, of course, to be Conservatives or Unionists a long time ago. They are now the insurrectionary party, the economic destruction party, the screw-the-Union party, the hard-border-in-Ireland party, the ideology-before-pragmatism party, the millenarian party, where all that matters is the rapture of Brexit. Go to your final reward having seen off Johnny Foreigner and taken back control.

Neither David Cameron (the true begetter of Brexit) nor Theresa May is now the presiding spirit of the Tory party. Robespierre is – it’s perpetual revolution or nothing. How true Conservatives feel about this is an interesting question. Did they always favour the strenuous politics of Robespierre or Pol Pot over the practised passivity of Lord Salisbury or Stanley Baldwin?

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A reshuffle beckons. The Eeyores must all go – Hammond, Amber Rudd (who looked grim faced as she emerged from her home to face the press on Monday), those old bores Damian Green and Michael Fallon. Let the Brexiters rule the roost – Johnson of course, David Davis, with his brainless fixed grin (he would have been an ideal major on the Somme), Michael Gove, with his well-turned platitudes, Andrea “laugh-a-minute” Leadsom with her calls for a patriotic press.

A purge of the moany remainers will open up positions for people who can really cheer us up. Let’s have Jim Davidson at defence, Ken Dodd at the home office, Mr Blobby as chancellor and the late Kenny Everett as first secretary and deputy prime minister. Then we will have a true ministry of all the talents, and we can embrace Brexit with a smile on our faces and a song in our hearts.

As the incoming home secretary once sang: “To me this old world is a wonderful place/ And I’m just about the luckiest human in the whole human race/ I’ve got no silver and I’ve got no gold/ Just a whole lot of happiness in my soul.” How can a stable, well-run, progressive nation possibly compete with one that is thoroughly tickled by this wonderful new adventure?

• Stephen Moss is a feature writer at the Guardian