Sir Keir Starmer said “every vote has to be earned” as he visited Hartlepool on the final weekend of campaigning before Thursday’s by-election.
Labour is looking to hold on to the so-called “red wall” seat and see off a challenge from the Conservative Party.
Dr Paul Williams, who was the MP for Stockton South from 2017 until 2019, is contesting the traditionally Labour-held seat after incumbent Mike Hill resigned in March amid sexual harassment allegations.
During a visit to Liberty Steel in Hartlepool, his third to the by-election battleground during the campaign, Sir Keir insisted he was not concerned Labour would lose out to the Tories.
“Quite the contrary, I love coming here,” he told reporters. “I’m very pleased to be here, I’m delighted to be here and I know every vote has to be earned and that’s why I’m here.”
He declined to say where a loss in Hartlepool would leave him as Labour leader, instead saying: “This is about Hartlepool, it’s not about me, we’re fighting for every vote.”
Sir Keir has accused the Conservatives of being “hopelessly distracted by sleaze and scandal” in the run-up to the vote.
He pledged to voters that a government under his leadership would always ensure that “taxpayers’ money is spent wisely” as he looked to keep Boris Johnson’s spending on renovations for his Downing Street flat in the spotlight.
Reports have suggested that the Conservative Party leader spent as much as £200,000 on the refurbishment of his No 11 living quarters, with the Opposition party calling on the Parliamentary Commissioner for Standards to investigate the Prime Minister’s conduct over the flat revamp.
Separate probes by the Electoral Commission, the Cabinet Secretary and independent adviser on ministers’ interests Lord Geidt have already been announced.
Labour has also accused the Tories of handing out “crony” contracts worth billions of pounds to friends of the party during the coronavirus pandemic, leading Sir Keir to dub the Prime Minister “Major Sleaze”.
Writing in the Northern Echo, Sir Keir said: “Instead of tackling the issues that matter, the Conservative Party has become hopelessly distracted by sleaze and scandal. And it’s you and your family who feel the impact.
“At next week’s elections there is a very clear choice: Labour candidates who will be relentlessly focused on jobs, tackling crime and supporting your health.
“Or the same old Tories: sleaze, waste, one rule for them, and another for everyone else.”
He added: “The Prime Minister may not know the value of the pound in his pocket, but we know you do.
“The least people should be able to expect from their government is that taxpayers’ money is spent wisely. Under my leadership, it will be.”
Sir Keir was joined by deputy leader Angela Rayner on the campaign trail.