Labour leader Sir Keir Starmer will carry out a reshuffle of his shadow cabinet team on Sunday, the PA news agency understands.
It comes following poor election results in England as voters in Labour’s traditional heartlands abandoned the party.
Labour lost the Hartlepool by-election as well as seven councils and more than 200 seats, with a few results still to come in.
Sir Keir has already sacked the party’s deputy leader, Angela Rayner from her role as chairman and national campaign coordinator.
Prominent figures on the left of the party hit out at Rayner’s sacking, with former shadow chancellor John McDonnel calling the move by Sir Keir, “cowardly avoidance of responsibility”.
However, Sir Keir says he takes “full responsibility for Labour’s election results in England.
Surprise victories for Labour
The row came despite Labour faring better in Saturday’s results, producing surprise victories in the West of England and Cambridgeshire and Peterborough mayoral contests.
The party also won second terms in Greater Manchester and the Liverpool City Region with Andy Burnham and Steve Rotheram respectively.
Burnham, who is the bookies’ favorite to replace Sir Keir, despite not being an MP, said: “In the distant future, if the party were ever to feel it needed me, well, I’m here and they should get in touch.”
In London, Labour’s Sadiq Khan fought off Tory rival Shaun Bailey to win a second term as mayor in City Hall, while Marvin Rees won a second term as Bristol mayor for Labour.
He beat off competition from Green candidate Sandy Hore-Ruthven in the run-off after the Liberal Democrat and Conservative candidates were eliminated.
Tories complete hat-trick of victories
Elsewhere in England, The Tories completed their hat-trick of victories to go with their shock Hartlepool by-election win and stomping Tees Valley mayoral victory when Andy Street was re-elected as West Midlands Mayor.
By the close of Saturday, with results in from 129 of 143 English councils, the Tories had a net gain of 11 authorities and more than 280 seats, while Labour had a net loss of six councils and more than 220 seats.
Mr Johnson vowed there would be “no let up in levelling up” after his successful further dismantling of Labour’s so-called “red wall”, adding: “Voters have put their trust in Conservative representatives, councillors and mayors and we must deliver for them.”
In Wales – as in Scotland and England – the party in power was rewarded by the voters.
Mark Drakeford’s Welsh Labour avoided the kind of electoral drubbing Sir Keir endured on Friday.
With the final declarations made on Saturday, Labour ended with exactly half the 60 seats in the Senedd – one short of an overall majority – equalling its best ever results.
First Minister Mr Drakeford, who extended the majority for his Cardiff West seat by more than 10,000 votes, vowed to be “radical” and “ambitious” in government.