LET’S not be curmudgeonly. That was a helluva speech by Jeremy Corbyn. Labour’s Brighton conference closed in buoyant mood and, for the first time in decades, the Red Flag was sung with gusto and passion.

Corbyn’s speech was a triumph.

Of course, it did a lot of widely predicted things -- committing Labour to public ownership of all utilities, and warning business that the days of laissez faire, low taxation and deregulation would be over if he becomes the next occupant of 10 Downing Street.

READ MORE: We are the ‘party of unity’ Jeremy Corbyn tells conference ... while Scottish Labour burns

As expected, he took Theresa May’s wooden and well-worn snap election jibes and chucked them straight back over the political garden fence.

To cheers he declared that the Tories had managed to track down the “money tree” and forced it to cough up £100 million per DUP MP — a reference to the Tories dodgy electoral pact with the Ulster Unionists.

To hoots of laughter he recalled the PM’s taunt about a left wing “coalition of chaos,” and thanked her for “showing us exactly how that works”. Far from “stable and strong”, he said, the Tories stood revealed as “callous and calculating.”

Spot on.

Corbyn’s delivery was convincing and stumble-free. His manner veered between boyish enthusiasm for a new society where automation frees workers to enjoy leisure time and righteous anger about the neo-liberal politics that helped produce the Grenfell Tower disaster. His message was unmistakeable. Labour is a government in waiting, looking for the first opportunity to force an early general election. Of course, we all expected a bullish stance – but just as few thought Corbyn could lead Labour out of the doldrums in the last election, fewer still thought he could deliver such a well-crafted and unapologetically left-wing leaders’ speech.

He dared the editor of the Daily Mail to print 28 pages castigating Labour at the next election, because the 14 pages of bile printed before this year’s snap election only added 10 per cent to Labour’s vote.

He was personally modest – declaring that the two great stars of the election campaign were the Labour manifesto and the activists gathered before him, with not a mention of himself.

He was believably passionate about the underdog – proclaiming Labour will never blame migrants for the ills of our society but will stop bad bosses and a Tory Government from scapegoating foreigners while they cynically drive down wages.

And he was clever – conceding that elections are won from the centre ground but contending that centre is no longer fixed and has shifted dramatically thanks to the recession, austerity and the Brexit debacle.

Of course there are caveats.

Labour didn’t actually win the last election and therefore Corbyn is still technically a loser. But just as the SNP lost the indyref yet seemed to win the subsequent war of public opinion, the much-vilified Labour leader has acquired the air of a future Prime Minister while possessing mercifully little of Tony Blair’s arrogance or Neil Kinnock’s toe-curling complacency.

OK, it’s true that Corbyn’s speech still left us none the wiser about Labour’s plans for life after Brexit. And of course, it’s easy for an opposition leader to sound radical but much harder for a Prime Minister to deliver -- as Nicola Sturgeon can testify. And there’s that minor problem of age. Even though he has the jaunty demeanour of a forty year-old, Corbyn will be 73 at the next General Election, unless events, Brexit, or the grey men of the Tory Party carry Theresa May off earlier.

Still, despite all these caveats there’s no doubt Corbyn’s delivered a corker of a speech yesterday, that will force every other political leader to up their game this conference season.

A corker, that is, until he had to go and sound a bum note. Scottish Labour, said Corbyn, was making a comeback, spearheading the case for social justice in Scotland.

Purlease.

Suddenly I found myself questioning every other assertion in Corbyn’s leader’s speech.

Now we all know the man from Islington finds it hard to get his heid round awkward auld Scotia. Each visit north prompts another outbreak of wee howlers – most recently he didn’t know tuition fees and the bedroom tax don’t exist north of the border but a distinctive Scottish legal system does. Och well, I suppose they’re easy enough to overlook fae doon yonder.

But even a Labour astronaut, circling the globe could not fail to be aware of the on-going car crash that is Scottish Labour -- a party that looks destined to be trapped forever between policies designed to appeal to a British electorate and the distinctive political culture of Scotland.

Thus, as Jeremy Corbyn’s radical agenda began to win over voters in England, Scottish Labour led by Kezia Dugdale, openly backed his rival and questioned Corbyn’s credentials. OK – we all make mistakes and sometimes back the wrong guy.

But that was a miscalculation of epic proportions. Labour was set to be wiped out north of the border but avoided that fate (picking up seven seats) only because of the excitement generated by Jeremy Corbyn. Yes he is pro Trident. Yes – a lot of his “radical” policy ideas have already been enacted in Scotland by the SNP. But Corbyn is certainly a conviction politician whose disdain for managerial politics is obvious. Who can say that for the long succession of Scottish Labour leaders?

And now, the whole sorry tale of Scottish Labour looks set to hurple into a new fratricidal chapter.

As Corbyn was cheered for declaring that Labour would not tolerate abuse of one faction by another and would settle differences democratically through a vote, Scottish Labour was demonstrating the hollowness of that lofty aspiration.

Speaking to a Radio 5 Live interviewer from the “safety” of an Edinburgh studio rather the Brighton conference, former Scottish leader Kezia Dugdale said the suddenness of her resignation spoke a lot about internal problems in the Labour Party, confirmed that she now felt “freed up” to say what she thinks and hoped Labour would avoid a situation where having different views on particular issues was enough to make you an “enemy of the cause”.

This came on the same day that the Sun published details of a private conversation between Scottish Labour’s temporary and supposedly neutral “caretaker boss” Alex Rowley and a conference delegate in which he revealed he was backing Corbynite Richard Leonard in the latest leadership contest. Now of course, folk in the public eye are still entitled to have private views and private conversations. But the comments seemed to confirm that Rowley doubtless did set Anas Sarwar up for an SNP onslaught at First Ministers Questions last week, when he talked about “the millionaires not the millions”.

Such a deliberate act of cunning might suggest the left made a mistake in picking the slightly lacklustre Leonard in place of the rumbustious Rowley as the man to take on neo-liberal Sarwar — but none of these revelations help Scottish Labour put any of their troubles behind them.

READ MORE: Scottish Labour erupts into civil war after Rowley gaffe leads to attack on 'latest Jackie Baillie pish'

Indeed, in trying to paper over the chasms that clearly exist, the erstwhile leadership of Scottish Labour has managed to take the shine off Jeremy Corbyn’s stirring speech and confirm a pre-existing suspicion that he is a nice man without a scooby about what goes on north of the border.

Not bad going – even by luckless Labour standards.

But all the same, Nicola Sturgeon will be making sure her leader’s speech in a fortnight delivers enough vision, conviction and passion to leave Jeremy Corbyn standing.