The Conservative Party has won the Hartlepool byelection, taking the constituency for the first time since it was created almost 50 years ago.
A Labour source said: “These were always going to be tough elections for Labour.
“Keir has always been honest about the mountain we must climb to rebuild trust to win the next general election.
“Labour is listening and we will continue to change in order to win back the trust of working people in Britain and their communities.”
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 byelection represents to their parties.
Meanwhile, counts in more than half of Scotland’s parliamentary constituencies are to begin on Friday as the country awaits the outcome of its most important election since devolution, one that could speed up an independence referendum.
Votes in some 46 of the 73 constituency seats in Scotland will be counted from about 9am, with the first results expected from noon.
It is anticipated all 46 should be declared by Friday evening.
Then, from about 9am on Saturday, the remaining 27 constituency seats will be counted, after which the regional seats will be allocated.
Due to the Covid-19 pandemic, there is a staggered tallying up of ballots for the 2021 Holyrood election, with all results expected to be declared by Saturday evening.
This year’s election is considered to be one of the most important since the Scottish Parliament opened in 1999.
With the Scottish National Party (SNP) set for another five years in government, first minister Nicola Sturgeon will no doubt ramp up the pressure on Westminster to grant the powers for another vote on Scottish independence.
Her opponents in the Tory, Labour and Liberal Democrat parties have stressed the importance of focusing on Scotland’s recovery from coronavirus instead. But the SNP leader and her party have said no referendum will be held until after the immediate health crisis is over, and they insist powers gained through independence would improve the recovery in Scotland.
Ms Sturgeon has said another pro-independence majority in the Scottish Parliament, including the Greens and Alba Party seats, should be enough to let Scots vote again on whether they want to leave the UK.
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.