Who will Jeremy Corbyn's team blame now? They can't blame the Blairites. The moderate wing of the Labour party stopped agitating against the leader when Owen Smith was defeated. They can't really blame the media because the media too has gotten bored of Corbyn not doing anything. A news feature based on him would be like watching a nature programme about lions napping. There is no action shot, no adventure. The truth is no-one really cares what Labour does anymore. It's the worst kind of insult.

Who is left to blame? Last night Labour lost to the Conservatives in Copeland. It wasn't narrow either. They got a proper spanking – down five points, with the Tories up eight. The Lib Dem vote was up four, while Ukip fell by nine. It's tempting to put together a Brexit-flavoured explanation for that – Ukip to Tories, Labour to Lib Dems – but there were plenty of other things going on, including the crucial nuclear issue. Regardless, the result suggests that current opinion polls – themselves unspeakably bad for the opposition – might still be underestimating Tory support, as they did in 2015.

Do not underestimate the extent of this loss. Labour lost against the governing party. In a by-election. Yes, the Tories replaced their leader so they are enjoying a brief upswing in popularity, as Gordon Brown did  – although for far less time – and John Major before him. But regardless, a meat-and-potatoes opposition heading for defeat would still expect a healthy swing in its favour during a byelection. Corbyn lost votes . Labour figures now call Copeland a marginal. So a safe Labour seat for eight decades is now a marginal. That's where we are.

Who can they blame? John McDonnell blamed Tony Blair for his speech on Brexit last week. Corbyn himself blamed "the political establishment". It is not a convincing analysis. People rejecting the political establishment generally do not vote for the governing Tory party.

The truth is there is no-one else to blame. Their internal opponents have left them to it. The media have left them to it. Even the Tories have started ignoring them, since Labour promised away their ability to delay the Article 50 bill. This is Corbyn's failure and he owns it, completely.

So what happens now? The so-called Labour moderates have not just been silenced by the Owen Smith contest. They are also petrified by Brexit and the witch hunt against anyone who tries to 'thwart the will of the people'. Theresa May's steely gaze in the Lords this week, as peers debated amendments to the Article 50 bill, looks upon MPs as well, daring them to stand up and oppose her plans and be branded traitors to the country by her cabal of rabid newspaper supporters and parliamentarians. The only thing that unites the right and left of the Labour party is terror over Brexit and Brexit is the only political subject which matters.

There are quite a few people out there – some of them relatively influential – who want Labour to split and are prepared to dedicate money and time to making it happen. Some see it as a necessary precursor to a general realignment in British politics towards a new open/closed binary opposition. Under this theory, a Labour split might precipitate a Tory split later on in negotiations, if the economic side of things looks particularly dire.

That's still possible but intuitively it feels like if the Labour party was ever going to split it would have done so last autumn. Most MPs are too cautious for that sort of big decision. It can leave you out in the cold, friendless in parliament, foolish in the media and lost in your constituency.

And anyway most Labour MPs remain tied to the Brexit mast as the ship careers towards the storm. Corbyn's opponents in the PLP have no better ideas about how to deal with the party's predicament than their leader. You only need to see the unimaginative nature of interventions by people like Stephen Kinnock and Dan Jarvis to recognise that. They pursue a strategy for the one third of Labour voters who backed Brexit, but nothing for the rest. Corbyn supplies a strategy for no-one. In that sense they would be an improvement. A third is better than nothing, but it is not the basis for a successful leadership campaign.

There's just not much going on. Corbyn offers no hope. His opponents offer no hope. Labour does not appear prepared to split or to select a new leader. Instead it is just slumped on the floor, occasionally twitching, although even that sometimes seems too much for it now. The fact it can even win a by-election in Stoke is actually impressive. It shows the resilience of the Labour brand despite the utter poverty of those who represent it in parliament.

Ian Dunt is the editor of Politics.co.uk. His book – Brexit: What The Hell Happens Now? – is available now from Canbury Press.

The opinions in politics.co.uk's Comment and Analysis section are those of the author and are no reflection of the views of the website or its owners.