Sir Keir Starmer says he has a “renewed spring” in his step after Labour’s victories in Tamworth and Mid Bedfordshire – but warns there is still “a mountain to climb” if his party is to take power at the next general election.

Labour overturned two huge Conservative majorities in last night’s by-elections, dealing a double blow to Rishi Sunak in results viewed as significant markers ahead of a national poll next year.

But speaking to Sky News’ political editor Beth Rigby, the Labour leader said he “accepted victories like this humbly”, and there was still work to do to earn the “trust and confidence” of voters across the country.

Politics latest: Second by-election defeat on terrible night for Tories

“I know how big a task it is to get the Labour Party from where we landed in the last general election to a Labour majority at the next election,” said Sir Keir.

“That is a mountain to climb. We are climbing that mountain, we can see the summit with these victories. But we have still got to get there.

“So what [these wins] give me is a renewed spring in my step to take the team up a level again and show that we can now win anywhere and that former Tory voters are now voting Labour.”

He also played down comparisons to Tony Blair – the last Labour prime minister who secured three election wins – but said he hoped to “follow in the footsteps of a leader of our party who took us from opposition to power, and that’s where these results are so important as a step along their journey”.

The two contests were triggered by the high-profile departures of the areas’ previous MPs.

Former cabinet minister Nadine Dorries’s long drawn-out resignation in Mid Bedfordshire came in anger at being denied a peerage in Boris Johnson’s resignation honours list.

And in Tamworth, Chris Pincher resigned after being found to have drunkenly groped two men at London’s exclusive Carlton Club last year – an incident which helped trigger Mr Johnson’s exit from No 10 because of his handling of the situation.

Mid Bedfordshire saw the largest numeric Tory majority ever overturned by Labour at a by-election since 1945, as Alistair Strathern took the seat with a majority of 1,192 over his Tory rival Festus Akinbusoye.

This was despite the Conservatives having held the rural seat since 1931, and winning with a 24,664 majority in 2019.

In Tamworth, the party was defending a 19,600 majority, but a 23.9 percentage point swing to Labour saw that eradicated as Sarah Edwards defeated Tory Andrew Cooper by a majority of 1,316.

The historic result was the second-highest-ever by-election swing to Labour.

Labour mantra to not be complacent on full show

Rob Powell

Political correspondent

@robpowellnews

After romping to electoral success in traditional Labour-held seats in the 2019 general election, Boris Johnson continually said he knew people had lent their votes to him and the Tories needed to repay their trust.

Sir Keir Starmer is now making a very similar point.

Speaking in Mid Bedfordshire, the Labour leader put great emphasis on the need to “take this incredible victory humbly”.

And in his interview with Beth Rigby, he also repeatedly refused to get too excited, adopting a deliberately measured tone.

One of the party’s mantras right now is ‘don’t get complacent’ – and this is fully on show today.

All that said, off camera and behind closed doors there is a surging sense of confidence in Labour that was on display in the bars and receptions of their recent conference in Liverpool.

The irony of Mid Bedfordshire is that you wouldn’t bet against the Tories re-taking it come the general election.

That’s because part of the reason Labour took the seat is the vicious three-way fight with the Lib Dems and Tories that’s taken place here in recent weeks.

There will be a higher turnout come a national vote, with potentially more Tory voters turning up at polling stations and the attention of the Lib Dems likely to be elsewhere.

But it’s important to note that Labour doesn’t necessarily need to take places like Mid Bedfordshire to win the next general election.

And what this stunning victory will do in the weeks and months ahead is add to the broader sense that Sir Keir really is on the path to Downing Street, even if the Labour leader won’t say that himself.

The Tories have sought to portray the by-elections as mid-term blips, exacerbated by the difficulties surrounding the previous MPs.

The party’s chairman, Greg Hands, also claimed to Sky News that “the big problem” was Conservative voters “staying at home”, rather than switching allegiances.

“I [campaigned] more than 10 times in Mid Bedfordshire, five times in Tamworth, [and] I didn’t have a single person come to the doorstep saying that the solution to their problems was Keir Starmer and the Labour Party,” he said.

“We need to make sure, think about and reflect on particularly the large number of Conservative voters who stayed at home. We need to think about how to energise them.

“They realise this is a by-election which would not be determining who is the government. Rishi Sunak will carry on being prime minister.

“Things could be very different at a general election going forward. Governments traditionally don’t do well at by-elections and nor are by-elections necessarily a good prediction of how a future general election will pan out.”

But Sir Keir said the excuse “doesn’t really hold water”, telling Beth Rigby: “Tory voters did turn out and some of them turned out to vote Labour. That is the real significance of these victories.”

Elections expert Professor Sir John Curtice said the two results were “extremely bad news” for the Conservatives and suggested Mr Sunak was on course for general election defeat.

“This isn’t destiny, but it is a pointer and it is a pointer that, unless the Conservatives can fairly dramatically and fairly radically turn things around, then they are in truth staring defeat in the face in 12 months’ time.”

He warned the Tories risked seeing votes drift to Labour on the left and Reform UK on the right.

Labour’s Tamworth victor Ms Edwards used her victory speech to call on Mr Sunak to “do the decent thing and call a general election”, while in Mid Bedfordshire Mr Strathern said his win showed “nowhere is off limits for this Labour Party”.

While Tamworth was seen as a two-horse race between Labour and the Tories, the Liberal Democrats were also seen as being in the running for Mid Bedfordshire – prompting concerns that the governing party might squeak through on a massively reduced majority because of a split in the anti-Conservative vote.

Despite coming third in a seat they had hoped to win, the party was positive about the result, saying they doubled their vote share and if that was mirrored in a general election, it would mean winning “dozens of seats off the Conservatives”.

Deputy party leader Daisy Cooper told Sky News: “Clearly we were very disappointed not to win either of the by-elections… [but] we managed to win over thousands and thousands of supporters, votes from people who were former, lifelong Conservative voters.

“We feel as though we have been instrumental in helping to defeat the Conservatives in [Mid Bedfordshire]. And we hope very much to be instrumental in defeating the Conservatives at the next general election.”

Mr Sunak was out of the country as the by-election results came in, spending the night in Saudi Arabia on a tour of the Middle East in the aftermath of the Hamas attacks on Israel.