The scale of the electoral challenge facing Labour was laid bare overnight as the party haemorrhaged councillors at the local elections and Reform made significant gains.

Keir Starmer’s party went into Thursday’s local elections expected to lose up to 1,850 councillors, with senior figures describing the contest as “tough”.

Initial results painted a bleak picture for the prime minister, with Labour losing councillors in its traditional northern heartlands.

Reform were the runaway winners in north-east England. There were 12 seats up for grabs in Hartlepool and Reform won every single one of them. It means Labour, which had a slim majority and was defending six seats, is likely to become the opposition.

Because only a third of the council was being elected, Reform will not have an outright majority. The party will have to make deals with independents in order to take control.

Labour councillors and supporters were noticeably despondent at the count in Brierton sports centre. The town’s Labour MP Jonathan Brash watched his wife Pamela Hargreaves, leader of Hartlepool council, lose her seat.

He told the Guardian he was angry and he repeated his call for Keir Starmer to go.

“It has been a terrible night for the Labour party,” he said. “What I’ve seen here is extraordinarily good, hard-working Hartlepool people lose their seats. I’ve seen canvassers working night and day in this election and it’s all been for naught and the reason has absolutely nothing to do with them.

“They are delivering for this town, they have been delivering for this town and the reality is we need change at the top of the Labour party.

“I think the very best thing the prime minister could do now is address the nation tomorrow and set out a timetable for his departure. We can then have an orderly transition, one that, by the way, ensures the full breadth of talent within the Labour party is able to stand, should it want to.”

The turn out was 31.5%, slightly higher than the 28% of the last local election in 2024.

In Halton, Cheshire, Labour held two of the 17 seats it was defending as Reform UK gained 15 councillors in the first council to complete its count on Friday.

In some wards, Reform won with more than 50% of the vote in an area where last year Nigel Farage’s party won the Runcorn and Helsby byelection by just six votes.

Although Labour’s starting position means it retains control of Halton council, the shift in vote share combined with losses elsewhere in the north-west point to a difficult night for Starmer.

Those results included losses to Reform in Chorley, in Lancashire, and Wigan, in Greater Manchester.

Elsewhere, Redditch and Tamworth also changed from Labour to no overall control, while the Liberal Democrats took control of Stockport.

Wigan, represented in parliament by Lisa Nandy, Starmer’s culture secretary, saw Labour lose 20 seats and Reform gain 23, but the authority remains Labour-controlled.

In Oxford city council, Labour lost two seats to the Greens but was expected to continue to be the biggest party and maintain its minority administration after winning in 10 wards. The Greens gained three seats overall after winning nine wards.