Sir Keir Starmer has categorically ruled out imposing capital gains tax on the sale of people’s homes, saying it was “desperate” tactics from the Tories to suggest he would.

The Labour leader said he could “absolutely” guarantee that would not happen.

“There was never a policy so it doesn’t need ruling out, but let’s rule it out in case anybody pretends that it was,” he said.

Labour had explicitly ruled out increasing the rates of income tax, VAT and national insurance.

But it has largely responded to questions about its wider tax policy by saying there were “no plans” in the manifesto that required tax hikes beyond those set out in the document.

This has led the Tories to claim that Labour is planning a series of secret tax raids, including the possibility of making the sale of a primary residence liable for capital gains tax.

Sir Keir told reporters on a visit to a hospital in Worksop: “This was just a desperate story by the Tories in relation to capital gains tax on primary residences.”

He insisted he was not being cautious about responding to Tory attacks over tax.

“The reason for that is I reject the idea that the only levers a prime minister has to pull are either the tax lever or the spend lever.

“There’s growth – this has been the missing part for the last 14 years, it has been the missing part of this General Election campaign, frankly, a discussion about growth.

“Our manifesto is a manifesto for growth and a serious plan for growth.”

Meanwhile, veterans minister Johnny Mercer warned would-be Reform UK voters they risked handing “unchecked” power to Sir Keir if they prevented the election of Tory MPs.

In the latest sign that the Tories are now fighting to maintain as many MPs as possible as an opposition party, Mr Mercer said: “If you vote Reform, you’re going to get a Labour government”.

The Tory strategy of warning voters that backing Nigel Farage’s party could result in a Labour landslide has intensified, after an opinion poll put Reform ahead of the Conservatives.

An average of all polls that were carried out wholly or partly during the seven days to June 14 puts Labour on 42%, 21 points ahead of the Conservatives on 21%, followed by Reform on 15%, the Lib Dems on 11% and the Greens on 6%.

Mr Mercer acknowledged the Tories were facing a tough campaign and there were occasions when “morale plummets”.

He told Sky News: “This election is tough, right? And it was always going to be tough after 14 years in power, and clearly the campaign’s been up and down as well.

“But I don’t see those polls reflected on the doorsteps.

“I think people are focusing in and as we get closer to that election, they’re really starting to see that clear choice, if you like, between Starmer, who every time he goes on TV just refuses to rule out serious things like capital gains tax, like he did last night, and the Conservatives, who are dealing with a tricky situation, but actually if you look at the manifesto, there’s a real bold plan there.”

He added: “If you vote for Reform, you’re going to get a Labour government, you’ll get unchecked power from a Labour government to come in and change the face of this country into something that I don’t believe it is, I don’t think it is a left-wing country.”

On Times Radio, Mr Mercer acknowledged that his seat, which has a notional majority of 13,262 if the 2019 contest was fought on the current boundaries, was at risk.

He said Conservative Campaign HQ (CCHQ) “should be worried about me, it’s very hard out there on the doors and the polling is very much against us”.

He said he was fighting for every vote “and that’s what politics is about, getting out, having a conversation with people and, to be honest, that side of it is really encouraging, it’s great fun”.

“It’s when you come home and see the media and all the rest of it that morale plummets,” he added.

Prime Minister Rishi Sunak will not be on the campaign trail on Saturday and is due to attend a major international summit on Ukraine in Switzerland.

But Labour leader Sir Keir was highlighting his party’s plans for the NHS with his hospital visit.

In an interview with The Times, shadow health secretary Wes Streeting said he would not judge people who went private instead of using NHS treatment.

“People who are going private are refugees, not traitors,” Mr Streeting said.

“People are voting with their feet, through no fault of their own, I don’t judge people who have paid to go private – they’re fleeing from the NHS.”

Sir Keir was forced to defend Labour’s claim that NHS waiting lists could rise to 10 million, despite a think tank saying that was “highly unlikely”.

Responding to the Institute for Fiscal Studies’ criticism, Sir Keir said: “What we’ve said is if the list was to increase at the same rate as it’s increased since Rishi Sunak has been Prime Minister, we will get – if we had more five more years of the Tories – to 10 million on that waiting list.

“That’s why it’s so important that this election is seen as a change election, the opportunity to turn the page on that, usher in a Labour government that is absolutely committed to rebuilding our country and starting, on day one, with our planning for 40,000 appointments each and every week.”