British Prime Minister Rishi Sunak’s leadership came under severe pressure on Friday as his party faced one of the worst local election results for the governing Conservatives in 40 years, with the only glimmer of hope coming from a Tory Mayor in northern England holding on to his seat.

Tory Mayor Ben Houchen was re-elected for a third term in Tees Valley and gave his party leader something to cheer about amid results Sunak admitted have been “obviously disappointing”. But rebels from within his party are expected to renew their attacks on the British Indian leader after the Opposition Labour Party made definitive gains, including overturning the Tory majority in the Blackpool South by-election which was necessitated following a resignation amid a lobbying row.

Labour Leader Sir Keir Starmer declared the result as a "seismic" victory and an overall poll verdict in favour of the party as it comes on the eve of a general election, expected later this year.

"Blackpool speaks for the whole country... This is the one contest where voters had the chance to send a message to Rishi Sunak's Conservatives directly, and that message is an overwhelming vote for change," said Starmer of the by-election.

"The message to Rishi Sunak is clear. It's time for change, it's time for a general election," he said.

The Labour candidate in Blackpool South, Chris Webb, defeated Conservative David Jones in the constituency which the Tories had won from Labour under former prime minister Boris Johnson in 2019. The swing of 26 per cent from the Tories to Labour has been characterised as the third biggest in a by-election since 1945.

“We're probably looking at certainly one of the worst, if not the worst, Conservative performance in local government elections for the last 40 years,” eminent pollster Professor John Curtice told the BBC.

The by-election took place alongside local elections around England and Wales, in which voters elected their local councillors who manage day to day issues such as waste collection, roads and local infrastructure as well as crime fighting.

“I know that come with the general election they’re (voters) going to stick with us because they don’t want to be taken for granted. They know that it’s you and the Conservatives that are building a brighter future for Teesside and a brighter future for Britain,” said Sunak as he joined the victorious Mayor Ben Houchen in Tees Valley, northern England.

Meanwhile, Labour declared victory in “Rishi Sunak’s backyard” after David Skaith beat the Conservatives’ Keane Duncan in the first ever York and North Yorkshire mayoral contest. It refers to Sunak’s parliamentary constituency of Richmond (Yorks), implying that it could be indicative of things to come in the general election.

“This is a truly historic result in York and North Yorkshire. Keir Starmer’s Labour party is now winning in Rishi Sunak’s backyard. The Prime Minister’s own constituents have taken a look at the two parties and chosen Labour,” a Labour spokesperson said.

The results will continue to pour in over the weekend, with the overall picture expected to be clear by Sunday. But the early indications are that Labour has taken control of a number of local authorities in the regions that had turned away from the party in favour of the Tories over its anti-Brexit stance.

Meanwhile, Tories look set to lose hundreds of seats, with the far-right Reform UK also making some impact. This will also worry the Conservatives for the general election if traditional Tory voters are seen to be drawn to this new avatar of the pro-Brexit UK Independence Party (UKIP). In another trend likely to continue to resonate during a general election, there is evidence in areas with a significant Muslim population that Labour's stance to not strongly condemn Israel in the Gaza conflict is hurting the party.

Most of the mayoral results are expected over the weekend, with London’s Labour Mayor Sadiq Khan hoping to be re-elected for a third term. He was challenged by British Indian businessman Tarun Ghulati, who thanked voters for the support he received in the campaign.

“I had overwhelming support from India and all over the world and want to thank everyone for the support and blessings,” he said.

Among the other mayoral polls, the Tory Mayor of the West Midlands is hoping to hold on to his seats. There other mayoral contests taking place include Greater Manchester and Liverpool City Region, with the East Midlands, the North East, and York and North Yorkshire electing mayors for the first time. Besides councillors and mayors, around 37 police and crime commissioners are also being elected in some parts of England and Wales.