On Monday morning, I bumped into a senior member of the shadow cabinet, who was standing with a pair of aides to Ed Miliband at Euston station, all of them clutching trolley bags. "We're off to save the union," said the shadow minister, with a grin. "And we're not coming back till it's saved."
Well, the 307-year union between England and Scotland is now officially safe, with 55% of Scots voting 'No' to independence in yesterday's referendum. The question of Scottish independence, to quote David Cameron, is now "settled for a generation".
How about the question of the next election? Is that "settled" too? Judging by the lacklustre Better Together campaign, which was Labour-dominated from the start - from its campaign director Blair McDougall, a former New Labour special adviser, to its chair Alistair Darling, the former chancellor, to its de facto chief strategist Douglas Alexander, the shadow foreign secretary - the Opposition have much work to do between now and next May's general election.
Some senior Labour figures aren't happy with the style or substance of the pro-union effort. "The truth of the matter is that we couldn't have designed a worse fucking campaign," a disgruntled member of the shadow cabinet tells me. "It was shocking."
He points to the relentlessly negative tone employed by 'No' campaigners, the lateness of the so-called devo-max offer, the obsessive focus on economics rather than identity, and the failure of Labour campaigners to distance themselves from the "toxic Tories".
Despite the referendum being held in Labour's Scottish heartland - where party founder Keir Hardie was born, where three of the last four Labour leaders were born, and where the Opposition currently holds 41 of the 59 parliamentary seats - there was little sign that the party had a clear grip on it message or its policies.
"Scottish Labour is fucked," says another shadow cabinet minister, who also went up to campaign north of the border. "They've proved they can't organise a piss-up in a brewery."
The shadow minister mocks the idea that "you wait till 10 days before [the vote] to call in Gordon Brown and show some passion".
Much of the credit, on both sides of the border, for the unexpectedly strong anti-independence vote on Thursday has gone to Brown, who energised the 'No' campaign with a series of highly-charged public events in the final few days, culminating in the "speech of a lifetime" from the former prime minister on the eve of the referendum.
Brown himself, a master political strategist and veteran campaigner, kept his distance from Better Together and operated, effectively, as a one-man, anti-independence army for much of the campaign. It's believed his decision to offer Scottish voters 'home rule' powers in return for a 'No' vote wasn't coordinated with the prime minister, with the leader of the opposition or with Better Together's Darling, his former cabinet colleague.
"I'm not going anywhere near Better Together," Brown told a friend a few weeks ago. "It's part of the problem. That's why we're not winning."
Brown brought passion, energy and populism to a 'No' campaign dominated by much more dour, dry and uncharismatic figures from Labour. Better Together was fronted by "technocrats", says a senior Labour source, citing the names of, among others, Alexander, Darling and Scottish Labour leader Johann Lamont. The party's general election campaign in 2015 can't afford to be, he adds.
Alexander, who doubles up as Labour's election campaign coordinator, was drafted in earlier this year to help with Better Together's campaigning and strategy, and has since been blamed by critics within his party for the late surge from the 'Yes' campaign over the past few weeks. It was Alexander who was blamed for commissioning a two-minute television ad of an undecided Scottish "mother" discussing the referendum which was mocked on social media for being patronising and sexist. Press reports quoted Better Together figures referring to Alexander as “Rain Man”, after the autistic character played by Dustin Hoffman in the Oscar-winning movie, because of his inability to connect with ordinary people.
"Until Douglas became the chief strategist for the 'No' campaign, we were 20 points ahead," a Labour frontbencher and critic of Alexander wryly observes.
Had the Scots voted 'Yes', says the frontbencher, Alexander would have been "finished". "You can only have so much luck," he says, reminding me of how the shadow foreign secretary ran both Labour's (losing) May 2010 general election campaign and David Miliband's (losing) September 2010 Labour leadership campaign.
Others say it is unfair to blame Alexander, as he joined Better Together so late on and, they add, the 'No' side won in the end - and, despite the last-minute jitters, won comfortably, by a 10% margin.
Still, the negativity of the message, the failure to offer an alternative and positive vision to the 'Yes' campaign, the reports of a dysfunctional working environment within Better Together and the inability to hold onto a 20-point lead worry some Labour strategists as they turn their attention back to Westminster and the general election.
"Despite plenty of people, including Gordon Brown, saying you've got to have a positive message, a positive alternative to the 'Yes' campaign, Darling and Alexander wouldn't do it until it was forced on them by Brown himself, from the outside," one of Labour's savviest strategists tells me, as he arrives back in England from Scotland.
And what's with the (belated) reliance on Brown? Was Miliband not up to the task of leading the Labour 'No' campaign? Why couldn't he mobilise Labour voters in Scotland on his own? He can't be blamed for 'Yes' campaigners surrounding and heckling him on campaign stops but he can be blamed for his failure to show direction and vision to anti-independence activists in his own party.
"Ed needs to look in the mirror," says a senior MP who would normally be considered a supporter of the Labour leader, adding that the decision to outsource the campaign's vision and direction to Darling and Alexander was "a catastrophic blunder".
So too was his seeming complacency. Six months ago, says a well-placed Labour source, not a single member of Miliband's team was worried about the Scotland result; they were all convinced that the 'No' campaign was on course for an easy victory. None of them saw the late Salmond 'surge' coming. "Anyone who says otherwise isn't telling the truth," says the source.
"The Labour Party, under Miliband's leadership, has had two years to prepare for this moment and never really did because it never really took [the Scottish referendum] seriously," adds the Labour strategist.
Members of the leader's inner circle push back hard against this narrative. "Ed's been to Scotland 14 times since March," says an ally of the Labour leader. "He also deployed resources from English marginals to the [Better Together] campaign. I don't think there was complacency [on his part] or a failure to see this as a huge challenge."
Why then was there so little effort from the Labour leadership to engage with the arguments over devolution of power, decentralisation and localism, beyond the Adonis Review's June proposal to divert £30 billion worth of funding to cities and regions? Why was it left to Brown to make the offer (bribe?) of extra 'home rule' powers and funds for Scots only days before the vote? Why were Miliband and his fellow shadow cabinet ministers caught on the hop by Cameron's instant, post-referendum demand for "English votes for English laws" [EVEL] and a "decisive answer" to the so-called West Lothian Question?
This last question is perhaps crucial: if Labour cannot come up with a softer form of EVEL then, as the devolution expert Alan Trench put it to me, "they'll find themselves saddled with a more rigid one to appease the Conservative right" and then even after they win an election, as one commentator put it, they'll be "in office but not in power, handing the Conservatives an effective veto".
"Ed has to pause and reflect on the lessons" of the referendum campaign, says a shadow cabinet ally of Miliband. For a start, he says, "Scotland can't be treated separately."
One of the key lessons of the Scottish referendum result is that the anti-politics mood generated by the Iraq war, the MPs' expenses scandal and the financial crash, among other things, still persists, affects voting intentions and is skilfully exploited by the likes of the SNP in Scotland and Nigel Farage's Ukip in England. The latter pushes a right-wing populist agenda while the former pushes a left-wing one; where's Miliband's own populist agenda?
The Labour strategist warns me that his party is "living on borrowed time. We're losing working-class supporters all the time; in the north to the Scottish nationalists and in the south to Ukip."
"We just look like an establishment party," explains a frustrated frontbencher, who says Miliband's message of change and reform is falling on deaf ears because he isn't matching his radical rhetoric with action. Labour is so keen to look like a serious, responsible, alternative government-in-waiting that it has ceded the populist, anti-establishment ground to the SNP in Scotland, Ukip and the Greens in England and - in Bradford, at least - George Galloway.
"[Scotland] shows there's a huge pent-up desire for change," a friend of Miliband told me earlier this week. "People don't want 'business as usual'. The worst thing any party could do if there's a 'No' vote is go right back to 'business as usual'."
The big question for Labour is: will Miliband heed his advice? With his party conference speech in Manchester only days away, and the general election just eight months away, the Labour leader can't really afford not to.