A few weeks ago I was chatting to a Tory MP who had served in the Armed Forces. ‘When you’re in the military, the key thing they teach you is to make a decision,’ he explained. ‘You may not like your options, but you have to choose one. Make a choice, or someone dies. And that’s Labour’s problem. They won’t make a choice. They’re just going to sit there and do nothing. And because of that, they’ll die.’

In the wake of Thursday’s by-election result in Richmond, it will again be easy for Labour to duck that moment of decision. A lot of the focus – and the fallout – has centred on Theresa May. Her own decision to indulge Zac Goldsmith and not run a Tory candidate has backfired spectacularly on her.

Yes, had she challenged Zac she would probably have still lost the seat. But at least she would have lost it, rather than simply gifting it to her opponents. And she would have sent the message that she was not prepared to tolerate little rich boys playing silly games.

Labour's sunk (it just hasn't realised yet): A Titanic disaster starring Jeremy Corbyn

Sarah Olney’s triumph has also emboldened the beleaguered Remainers. ‘The people of Richmond Park and North Kingston have sent a shockwave through this Conservative Brexit Government, and our message is clear: we do not want a hard Brexit,’ she proclaimed in her victory speech.

Maybe, but I’m not convinced Theresa May will be weighing the 20,000 Lib Dem voters of Richmond against the 17.5 million who voted nationally for Brexit, and saying: ‘Richmond has spoken – we have to think again.’ In fact, I suspect she will see this as an opportunity to again define herself as being against the despised ‘London elite’.

This result was not a hammer blow to Brexit, or the May Premiership. But it was a hammer blow to Jeremy Corbyn and Labour.

Richmond does not – as some have claimed – reveal a Britain that has split in two. Instead, it shows a nation that is now divided into three distinct tribes. There is Brexit Britain, tired of ultra-liberalism, and hungry for a return to ‘traditional values’. There is Remainer Britain, horrified at what it sees as a conservative counter-revolution, and committed to driving the ‘Alt-Right’ barbarians from its progressive gates. And there is Middle Britain – majority Britain – which has no real desire to rally behind either of these cultural battle- flags, and just yearns for a modest but measurable improvement in daily life.

Labour no longer represents any of these three factions. It does not know how to speak to them. It does not know how to identify with them. It no longer even adopts the pretence of trying to speak to or identify with them.

The only people Labour cares about are its own party members

The only people Labour cares about are its own party members. That phantom army that exists solely to maintain a steely-eyed vigil over Jeremy Corbyn’s political life-support machine, and to terrorise Labour MPs who dare step out of line.

Labour is now the official Opposition in name only. This is the week that has effectively seen it become the fifth party of British politics. The Conservatives have captured Middle Britain and a fair chunk of Brexit Britain. Ukip speaks for the rest. The Lib Dems are becoming the standard bearers for Remain Britain, except in Scotland, where the SNP has fashioned a one-party state. Labour is now an irrelevance. Actually, Labour is now an embarrassment, reduced to scrabbling around with the Monster Raving Loony Party to try to save its candidate’s deposit.

And yet no one is planning to do anything about it. No one from within Labour is prepared to take a decision or make a choice.

At the start of last week, as Paul Nuttall was anointed Ukip’s latest leader of the month, a consensus formed. Labour had to move to counter the threat to its traditional, Northern, white, working-class vote. It needed new messages on immigration, welfare and Europe. Just 96 hours later that consensus had been junked. Now Labour had to move to counter the threat of a Lib Dem resurgence. It had to defend its metropolitan heartlands and adopt a clear anti-Brexit stance. Labour had to speak for the 48 per cent.

Labour does not have a strategy. Instead it is indulging in an increasingly frantic game of political whack-a-mole. ‘Get that Northern Brexit voter!!! No, wait, get that metropolitan Remain voter!!! No wait, get that Just About Managing voter!!!’

This has to stop now. Labour – its MPs, its members and supporters, its financial backers – have to take a step back, take a deep breath, and face reality.

In the post-Brexit world, the Labour Party is no longer fit for purpose. It is carrying too much political baggage. The divisions are now too wide, the scars are too deep. Labour, as currently branded and constituted, can no longer reach a sufficient political critical mass to govern. It cannot even get close to a working majority. The constituency to deliver one simply doesn’t exist any longer. Up until now I’d been sceptical about talk of a new Centre-Left party. But this morning I don’t see any alternative.

Yes, it represents a formidable organisational challenge. But no less formidable than trying again to breathe life into the Labour corpse.

Those people – myself included – who had seen the removal of Jeremy Corbyn as the key to Labour’s salvation have been deluding themselves.

This is not Jeremy Corbyn’s fault. Labour – as opposed to New Labour – has not won an Election since 1974. Look across Britain, out across Europe and then out across the Atlantic, and the trends are clear. The liberal, identity-driven political model that Labour represents is broken. And it cannot be glued back together.

Labour will stagger on, chasing its own shadow for a couple more years. But the moment of reckoning with the voters is approaching. And when they have had their say, then a choice – a final choice – is going to have to be made.

As gloomy economic prognostications threaten to cast a shadow over the festive season, I bring some upbeat tidings.

A concerted lobbying effort has been made by the Scotch Whisky Association over what it sees as the unfair – some would say penal – 77 per cent tax imposed on the old aqua vitae. And according to Westminster insiders, those efforts are finally bearing fruit.

A mole informs me: ‘Chancellor Philip Hammond met with them this week on his trip to Scotland and he said he was sympathetic to their case.’ A tax cut on whisky? That would certainly soothe the sting of Brexit.

Has Mogg met his match?

Jacob Rees-Mogg – the uber-retro MP for North East Somerset, has a new (and rather unlikely) admirer. Georgia Toffolo, star of reality TV show Made In Chelsea, has confessed to her Twitter followers: ‘Guys, I really like Jacob Rees-Mogg ♥♥♥.’ The glamorous Miss Toffolo has previously been romantically linked to George Lineker, son of Match Of The Day presenter Gary, and fellow reality stars Francis Boulle and Richard Dinan. ‘Made In East Somerset.’ It’s got a ring to it. But sorry Georgia, Jacob’s already spoken for.

Jacob Rees-Mogg – the uber-retro MP for North East Somerset, has a new (and rather unlikely) admirer. Georgia Toffolo, star of reality TV show Made In Chelsea

I understand Labour’s attempts to rebuild its relationship with the Jewish community suffered another setback on Wednesday. Shadow Foreign Secretary Emily Thornberry was due to address the Jewish News UK-Israel policy conference but pulled out to attend Fidel Castro’s funeral.