IT is a shock but not a surprise.

It is a shock because ruling parties do not make by-election gains: this is only the sixth in the last 100 years. It is a shock because Hartlepool has not elected a Conservative MP since 1959.

But it is not a surprise because in 2019, a Tory tsunami swept through the Tees Valley and County Durham. It lapped around Hartlepool, but the Brexit Party in this very Brexity town split the vote, allowing Labour to claim a 3,500 majority. This result, then, is just a continuation of 2019 – it shows that after Redcar, Sedgefield, Bishop Auckland and Durham North West, the blue tide is still coming in.

The biggest shock is the size of the majority. It shows that Labour’s Keir Starmer has not stemmed that tide in any way.

There seem to be three Bs at play here: Brexit, Ben and Boris.

Brexit has accelerated the gradual drift away from the Labour Party that has been happening in the North-East for decades. For Labour to select a remain candidate who lost his seat in 2019 – “if he’s not good enough for Stockton, he’s not good enough for Hartlepool” was a cry Tory canvassers tell me they heard on the doorsteps – was not a wise choice, despite his credentials as a virus-fighting doctor.

The shock election of Ben Houchen in 2017 as Tees Valley mayor proved to people they could vote Conservative without the sky falling in.

He proved that Tories were electable in these Labour heartlands, promising a new brand of practical politics – and, with the airport, delivering on that. Generations in this area have been scared of “the same old Tories”, but this is a new kind of Toryism.

And Boris allowed people to vote Conservative in national elections in a way that they couldn’t for a party led by someone like Theresa May or David Cameron. People talk about “voting for Boris” rather than for the Conservatives.

Despite all the media scandal, they still like him, they still like his positivism – it ties in with their pride of place and country that fuelled the Brexit vote. Boris bumbled into Hartlepool, kicking a football, elbow-bumping with his thumbs up and telling everyone that everything was going to be levelled up and everything will turn out alright.

Labour, by contrast, was just on the defensive about its Brexit stance and then it gave voters a negative impression of their own town by saying that their public services weren’t particularly good. Whether anyone would have been listening to the opposition leader immediately after Labour’s historic defeat of 2019 is debatable, even without the pandemic, but other than not looking like Jeremy Corbyn, Mr Starmer has not set out a vision of how fundamentally Labour has changed.

And he hasn’t addressed the existential question of whether Labour can change to represent working class voters who have no memory of the monolithic manufacturing industries on which the Labour movement was built.

Hartlepool is just one result so it is difficult to try and see a pattern, but already there are indications with the council results from Sunderland and Gateshead that the tidal wave is still rolling in – the council results in Durham, which is not just a Labour heartland but an absolute bastion, are going to be fascinating. They will give us a real indication of how deep the seismic shocks go.