Sir Keir Starmer said voters had sent Rishi Sunak a clear call for change in the last big test of public opinion before a general election.

Labour took Blackpool South in a by-election by a huge margin and won target councils across England.

Mr Sunak admitted results so far were “disappointing” although his party retained the Tees Valley mayoralty. The PM is being urged to call an immediate general election after suffering sweeping losses at the local elections in England.

Sir Keir said the Blackpool result which saw a massive 26% swing to Labour was a message to the Tory leader that it was time to move on and call a general election.

He said: “That wasn’t just a little message, that wasn’t just a murmur that was a shout from Blackpool. We want change and Blackpool speaks for the whole country – it’s saying that we’ve had enough now.”

In a rare bright spot for the Tories, Lord Ben Houchen was elected for a third term in Tees Valley, with a much reduced majority. He denied that he had shied away from campaigning as a Conservative or mentioning Rishi Sunak in his campaign literature.

When asked whether the Conservatives could win another term in government, he told the BBC: “There’s always a chance but the government needs to do a lot better at delivering for people… We need to give them the excuse to vote for us.”

Most other mayoral results including London, where Labour’s Sadiq Khan is aiming to win a third term – will come on Saturday.

MP Dame Andrea Jenkyns, a longstanding critic of Mr Sunak, urged him to listen to the electorate and change course, saying the party needed to “wake up, be conservative, or we lose”.

However Martin Vickers, the Conservative MP for Cleethorpes, backed Mr Sunak’s leadership and called the idea of changing leader “complete madness” just months away from a general election.

Labour will be particularly pleased to have regained control of key council targets Hartlepool, Thurrock, Rushmoor and Redditch – areas where they are aiming to win at the general election later this year.

There is evidence that Labour’s stance on Gaza is hurting the party in areas with a significant Muslim population. In Oldham, where two Labour councillors quit the party over Gaza earlier this year, Labour lost control of the council.

Labour MP Pat McFadden, the party’s national campaign coordinator, admitted “strong feelings” around the Middle East were “a factor” in the losses, adding: “I don’t think there’s any point denying that – it does get raised”.

Reform UK is doing well in the areas where it has fielded candidates – and nearly beat the Tories into second place in Blackpool South.

Reform leader Richard Tice said the results showed his party “is rapidly becoming the real opposition to Labour”.