Labour has all but conceded defeat in the Hartlepool by-election after a shadow cabinet member admitted the party was “not close to winning this”.

Shadow transport secretary Jim McMahon, who led the Opposition party’s campaign to hold the North East town, said it looked clear that Labour had not “got over the line”.

Such a humiliating defeat in a constituency that has voted Labour for almost 50 years will be a blow to Sir Keir Starmer’s leadership, after he stressed during the race to replace Jeremy Corbyn that he was the person to turn the outfit back into a winning force again.

We haven’t got over the line, that’s quite clear from the ballots

Mr McMahon told Sky News: “It is pretty clear in the way the ballots are landing that we are not close to winning this despite our best endeavours.

“We haven’t got over the line, that’s quite clear from the ballots.”

Votes are still being finalised in the Leave-backing constituency but Tory sources have predicted that the majority for blue candidate Jill Mortimer will be in the thousands.

Early results in council contests elsewhere also appeared to show voters deserting Labour, as ballots continue to be tallied up across England, Scotland and Wales following the Super Thursday polls – the largest test of political opinion outside a general election.

The Tories seized Redditch and Nuneaton & Bedworth councils in the Midlands from Labour, along with Harlow in Essex, while Sir Keir’s party saw heavy losses across North East local authorities.

Results from the Holyrood election – where the issue of Scottish independence was a main feature in the campaign – will come through later on Friday and Saturday.

Before then, the Hartlepool parliamentary contest is the main focus and it looks set to show how hard Sir Keir’s job of rebuilding support for Labour will be.

A Labour source said: “We’ve said all along the North East and the Midlands would be difficult.

“But, the message from voters is clear and we have heard it – Labour has not yet changed nearly enough for voters to place their trust in us.

“We understand that. We are listening. And we will now redouble our efforts.

“People don’t want to hear excuses. Keir has said he will take responsibility for these results – and he will take responsibility for fixing it and changing the Labour Party for the better.”

Shadow cabinet minister Thangam Debbonaire admitted the party’s message had not been cutting through.

“We’ve got a great team who cannot wait to be able to cut through more and I hear what people are saying, it’s not cutting through, I get that,” she told BBC’s Question Time.

“I think that’s a lesson for the Labour Party that we’re going to have to take into account.”

In a sign of the discontent on the Labour left, MP Lloyd Russell-Moyle appeared to mock the party’s attempts to change its image.

He said: “Good to see valueless flag waving and suit wearing working so well … or not?”

Hartlepool was held by Labour with a majority of 3,595 in 2019, even as other bricks in the red wall crumbled – in part due to the Brexit Party splitting the Tory vote.

Both Mr Johnson and Sir Keir made three visits during the campaign in a sign of the importance the by-election represents to their parties.

The Conservatives hope to achieve a “hat trick” of successes, winning Hartlepool and retaining the mayoralties in Tees Valley and the West Midlands.

Even with the Hartlepool result still looming, Communities Secretary Robert Jenrick had looked to pile the pressure on the Prime Minister’s rival, telling Sky News that “if it is even close, I would say that is a really serious indictment of Keir Starmer”.

Over the coming days results elsewhere could have an even more dramatic influence on the state of the nation’s politics.

Scottish National Party leader Nicola Sturgeon’s push for a second independence referendum means the stakes are high in the Holyrood contest, with results expected to be announced on Friday and Saturday.

The SNP is expected to emerge again as the largest party in the Scottish Parliament after the election, but it wants to win an overall majority of MSPs as it pushes for a second independence referendum – something polls suggest remains in the balance.

Mr Johnson has refused to countenance another referendum, setting up the potential for constitutional fireworks over the coming years if Ms Sturgeon gains the outcome she desires.

The SNP leader insisted her focus would be on tackling the coronavirus and rebuilding the economy.

But she said that “when the Covid crisis has passed, we will give the people of Scotland the opportunity to decide if they want the recovery to be in the hands of the likes of Boris Johnson and the austerity-driven Tories, or to put Scotland’s future in Scotland’s hands with independence”.

Mr Jenrick said: “We do not want to see Scotland, or indeed any part of the UK, now embroiled in a highly divisive and distracting constitutional wrangle.”

Results of the elections – which also include the Welsh Parliament, police and crime commissioners and English local authorities and mayors – are expected to continue filtering through until Monday as counting will take longer than normal due to coronavirus restrictions.

In Wales, 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.

That could mean talks with Plaid Cymru, whose leader Adam Price has committed to an independence referendum within five years if his party wins a majority.