Donald Macintyre's Sketch: The faithful loved Boris's jokes, but there was also a hint of leader gravitas

This would only have been a comeback if – a preposterous notion – he had ever gone away. It was much more alarming than that. The super-tousled hair, the mildly shambling gait, were the same as ever.

But this was Boris reconditioned. It was not just that the jokes were new, mainly, of course, at the expense of a Labour Party now in the grip of “militants with vested interest and interesting vests who idolise Hugo Chavez and toast the revolution in taxpayer-funded vintage Burgundy”. Or the even more extravagant boasts than usual. “Since I have been mayor, life expectancy has gone up in London by 18 months for women and 19 months for men… you live longer with the Tories, my friends.”

It was more that his messages to his own colleagues were sharper, the avowed “one nation” politics even infused with an occasional hint – amazing to relate – of un-Borisian gravitas.

He was helped by following Theresa May, whose draconian assault on asylum and immigration was the most right-wing in recent memory – no mean feat. Boris agreed that it was not up to Jean Claude Juncker to decide UK immigration policy. But that was not because “we… object to immigration in itself [try telling that to the Home Secretary] I speak as the proud great grandson of a Turk who fled his country in fear of his life… who was then assassinated by his political opponents – a fate I intend to avoid.” (A classic Boris mix of the serious and lightly menacing, this.)

No, it was about laws being made not in Brussels but “by people the British public can kick out at elections… and that means getting the right deal now from our EU partners as I know David Cameron can.” Note the “can” rather than “will”. This was Boris still crowd-pleasingly keeping his options wide open ahead of the great referendum.

And he railed as usual against Heathrow expansion – a decision which luckily will have gone through by the time he gets the Cabinet job Cameron promised him.

But it was his warning that “as we reform welfare… we [must] protect the hardest working and lowest paid, the retail staff, the cleaners, who get up in the small hours” that probably carried most freight.

The applause for this shot across the tax credit-cutting bows of SS Osborne testified to the mayor being the first speaker to generate any real excitement in the deadening Manchester auditorium.

They loved the gags. The Ed Stone had been the “heaviest suicide note in history”. Labour had been “piratically captured in a kind of social media twitstorm by what Harold Wilson once called a small group of politically motivated men”. And, in the long and overambitious comparison of British society cohering like a rugby scrum, the mildly risqué reference to his youthful past as a tight-head prop, bound “tightly and correctly – in my case to the hooker” [nervous laughter round the hall]. “Insert joke here, as Jeremy Corbyn’s autocue would say.” (Audible relief at anti-Labour punchline.)

A slightly more rounded Boris, then. His problem will be to get MPs to put him on the leadership shortlist. But it won’t be lost on his jostling, nervous rivals that if he jumps that hurdle, he could still be the party’s choice.