A jubilant Sir Keir Starmer has hailed a victory “against the odds” after Labour hung on to win in the bruising Batley and Spen by-election.

Kim Leadbeater squeezed home by just 323 votes after a bitter and divisive campaign that many had predicted the party would lose.

The result came as a huge relief to the beleaguered Labour leader after the party’s damaging loss in the Hartlepool by-election in May.

On a visit to the constituency to celebrate, Sir Keir paid tribute to the “incredible courage” of Ms Leadbeater in standing in the place where her sister, the MP Jo Cox, was murdered in 2016.

Speaking to reporters he acknowledged the Labour vote had been split by the campaign of left winger George Galloway who targeted the constituency’s Muslim voters in an attempt to topple his leadership.

However he suggested that they had been saved by former Tory voters who rejected the “divisive” politics of the Workers Party leader.

Meanwhile the Conservatives, who came within an ace of taking the seat in another sensational by-election result, admitted their campaign had been hit in the final days by the Matt Hancock affair.

It raised questions whether they could have won if Boris Johnson had sacked the former health secretary immediately the news broke he had been filmed kissing a close aide in his office in breach of social distancing rules.

Ms Leadbeater secured the seat, which Labour held at the 2019 general election with a 3,525 majority, with 13,296 votes, narrowly beating Conservative Ryan Stephenson on 12,973 with Mr Galloway third with 8,264.

Appearing alongside Ms Leadbeater in front of cheering supporters, Sir Keir, who could have seen his leadership threatened if they had lost, declared: “Labour is back. Labour is coming home”.

He said the result represented a “victory of hope over division” in a campaign “poisoned” by lies, harassment and intimidation.

While Mr Galloway had taken votes from Labour, Sir Keir said the Tories had paid the price for failing to criticise his tactics.

“We won this election against the odds,” he said.

“The Tories thought they could sit back, say nothing about harassment and they were wrong about that.

“Kim has won this because Tories in Batley and Spen, former Tory voters, voted for her.

“The left vote, the Labour vote, was split but we won.”

Earlier an emotional Ms Leadbeater, who thanked the police for their protection during the campaign, said she would seek to heal the divisions that had been opened up in the constituency.

“If I can be half the MP Jo was I know I will do her proud and I will do my family proud,” she said.

It followed a campaign marked by accusations of violence and dirty tricks as Labour supporters and Mr Galloway’s Workers Party battled for votes in the constituency’s Asian communities.

At the final weekend, Labour activists said they were pelted with eggs and kicked in the head, while police said an 18-year-old man had been arrested on suspicion of assault in connection with an attack on canvassers.

Ms Leadbeater was also confronted by a man who challenged her over the situation in Kashmir and her stance on LGBT education in schools amid what he said were concerns from Muslim parents.

Mr Galloway said he would take legal action to get the result set aside, claiming his election effort had been damaged by a “false statement” that he had laughed while Ms Leadbeater was abused on the campaign trail.

“The whole election campaign was dominated by lazy and false tropes about our campaign, about the thousands of people that voted for us, about their motives for doing so, in a way which defamed them as much as it defamed me,” he said.

For the Conservatives, Mr Johnson said they fought an “incredibly positive campaign” achieving the third largest by-election swing to a government party since the war.

Party co-chairwoman Amanda Milling acknowledged the final result was “disappointing” but insisted it is not a “great win” for Labour.

“It was a very, very close result.

“Governing parties don’t gain by-elections and actually taking it to such a small number of votes is in itself a tremendous result,” she told Sky News.

She acknowledged that the disclosures about Matt Hancock had hurt them in the final days of the campaign.

“It was something that came up on the doorstep, I have to be honest about that.

“They (voters) had some issues over the weekend in terms of what happened,” she said.