Boris Johnson has described the early election results as “very encouraging” after hopes of a Labour revival were dealt a crushing blow when the Conservatives won the Hartlepool by-election.

Speaking to reporters in Coventry, the Prime Minister said: “I know that the results have been coming in since this morning and there’s clearly a lot more to go, and it’s early days, but it’s a very encouraging set of results so far.

“I think that’s really because we have been focusing, as a Government, on our priorities, the people’s priorities, and bouncing back from the pandemic as much as we can and getting through it.”

Mr Johnson said he would say more later on “in Hartlepool”, where the Tory candidate Jill Mortimer took the seat – which had been Labour-held since it was formed in 1974 – with a majority of 6,940.

Speaking at the Severn Trent Academy, the Prime Minister added: “It’s been very nice to be here at Severn Trent talking to them about the 500 Kickstarters they’re employing, which is, I think, what everybody wants to see as we go through towards the end of the roadmap – really making sure that we’re getting people into work, getting the economy bouncing back very, very strongly in a way that I know it will.”

Shadow communities secretary, Steve Reed, earlier called Labour’s defeat in Hartlepool “absolutely shattering” after Ms Mortimer gained 15,529 votes – more than half the total cast – with Labour’s Dr Paul Williams, trailing on 8,589.

The result has provoked a furious reaction from the Labour left who have said the party must now change direction.

Former shadow justice secretary Richard Burgon said the party needs to “urgently change direction”.

“We are going backwards in areas we need to be winning,” he tweeted.

“Labour’s leadership needs to urgently change direction. It should start by championing the popular policies in our recent manifestos.”

However, Mr Reed insisted they would double down on the more centrist approach taken over the past 12 months.

“What this shows is that, although we have started to change since the cataclysm of the last general election, that change has clearly not gone far enough in order to win back the trust of the voters,” he told BBC Breakfast.

In her victory speech, Ms Mortimer said the result – overturning a Labour majority of more than 3,500 at the 2019 general election – was “truly historic”.

“Labour have taken people in Hartlepool for granted for too long. I heard this time and time again on the doorstep,” she said.

Early results in council contests have also been successful for the Conservatives, with the party taking Redditch and Nuneaton and Bedworth councils in the Midlands, along with Harlow in Essex and Northumberland.

Labour are braced for more bad results over the weekend as votes are counted in local elections across England.

Mr Reed denied Sir Keir’s leadership had been a problem and said they would work “tirelessly” to rebuild trust in the party.

“I’m very comfortable that we now have a leader that the country could see as an alternative prime minister – the problem is the Labour Party itself,” he said.

Votes are also being counted in the Scottish elections to Holyrood, where the issue of independence was a main feature of the campaign.

Scottish National Party (SNP) leader Nicola Sturgeon is pushing for a second vote on independence and the party is expected to emerge again as the largest party in the Scottish Parliament.

Results will also come in from Wales, where Mark Drakeford hopes to maintain Labour’s grip on the Senedd – but he may find himself forced to forge a new coalition to stay as First Minister.