If all it took to secure Britain’s long-term prosperity and security was some sub-Churchillian rhetoric, then the nation could rest easy for as long as Boris Johnson is able to serve up his unique style of bombast. “Let the British lion roar”, as Mr Johnson said, perhaps believing that such a mythical beast exists, perhaps cohabiting somewhere in a multi-occupancy wardrobe with a witch and their universal credit payments unaccountably delayed.

A Boris Johnson speech is a special exercise in multi-layered irony. No one, not in that hall in Manchester, not in the wider country, not in Downing Street and especially not the lad himself, seriously believes that he and every member of the Cabinet agrees with “every syllable” of the Prime Minister’s Florence speech.

It is the sort of hyperbole that is so comically extreme it is designed to transmit an unmistakable hint of mockery, both of that woolly speech itself, of the woman who gave it, and of the attempted clampdown on Boris freelancing activities in recent days.

Without much recourse to tedious detail – something that would be bound to get him into some difficulties once again – his rhetorical, emotional, witty commitment to Brexit was meant plainly to put clear Eurosceptic water between himself and others in the Cabinet, such as the Chancellor and the Home Secretary, who do think, as the Foreign Secretary puts it, that the Brexit vote was indeed a “plague of boils”.

There may have been a little more sincerity to Mr Johnson’s personal praise for the Prime Minister and her tribulations – in truth more pitying than admiring – but the rest of it was a simply a coded reminder to the country, if it needed it, that he is still available to become prime minister in this hour of peril – 1940 all over again, perhaps.

Mr Johnson’s effort followed a lacklustre and unusually curt address by the Brexit Secretary, David Davis, one that did nothing for any political ambitions he might himself harbour. Just as he once blew his chances of winning the leadership more than a decade ago with a poor conference speech, contrasted with the compelling vision offered by his then young rival David Cameron, so again Mr Davis funked it. The contrast with “Boris” was as stark as it could be.

Do they want Boris? The members plainly do, and the “Moggmentum” movement seeking more power and influence for the grassroots, mirroring the revolution in Labour, could gather so much pace that it delivers it to Mr Johnson out of sheer desperation and frustration.

Yet the same logic that saw his leadership campaign falter last year, and which has thus far kept him out of No 10, persists. As his former friend Michael Gove pointed out, Mr Johnson lacks certain key personal qualities that would qualify him for that office – and nothing we have seen of his stewardship of the Foreign Office contradicts Mr Gove’s damning verdict.

The Tories are still wary of more self-indulgent disruption and instability, something that could conceivably undermine the very existence of the Government and the whole Brexit project. A combination of a Jeremy Corbyn-led Labour government and hard Brexit is not a vista any Conservative could face with equanimity.

The public would rightly wonder what on earth the governing party was playing at. More to the point, Mr Johnson would most likely deliver an even worse Brexit than even Ms May will manage, if the country allows Brexit to proceed that far. The loathing and contempt that the Europeans feel towards Mr Johnson (and cordially returned by him) cannot be overestimated. Insofar as such personal factors matter, Mr Johnson’s personality is a net negative for the British national interest.