Keir Starmer is on a collision course with the hospitality industry and political opponents after signalling plans for major curbs on outdoor smoking.

The proposals, not denied by the prime minister, would potentially prohibit tobacco use outside pubs and restaurants, including on pavements. The restrictions would come on top of existing plans to gradually outlaw smoking year by year.

While the latter proposal was devised under Rishi Sunak, the Conservatives argued restrictions on outdoor smoking were about “social control”, with Priti Patel – among those standing to replace Sunak as Tory leader – calling them “beyond stupid”.

The plans were met with despair by the pub industry, which claimed restrictions on outdoor smoking could harm a fragile sector still recovering from Covid. However, health experts backed the idea, while polling showed it had majority support among every demographic and voting group apart from Reform UK supporters.

The plan, first revealed via documents leaked to the Sun, would restrict outdoor smoking outside pubs and restaurants, as well as clubs, and at universities, children’s play areas and small parks, and potentially shisha bars. It was unclear whether this could also cover vaping.

The measures would be included in an already-announced tobacco and vapes bill, which intends to gradually make all smoking illegal by prohibiting the sale of tobacco to people born on or after January 2009. When this was announced in July’s king’s speech, it did not mention changes to outdoor smoking.

As public health is devolved, the measures would apply to only England, with the other UK nations deciding if they wanted to follow suit.

Asked about the report during a visit to Paris, Starmer did not deny the plans. “My starting point on this is to remind everybody that over 80,000 people lose their lives every year because of smoking,” he said.

“That is a preventable death, it’s a huge burden on the NHS and, of course, it is a burden on the taxpayer. So, yes, we are going to take decisions in this space, more details will be revealed, but this is a preventable series of deaths and we’ve got to take action to reduce the burden on the NHS and the taxpayer.”

While the precise curbs are likely to change after consultation, it is understood ministers are in favour of many of the suggested ideas.

The hospitality industry figures, and pub owners in particular, said they were concerned the measures could prompt renewed uncertainty, even with official statistics showing only about one in 10 British adults still smoke.

Kate Nicholls, the chief executive of UKHospitality, which represents thousands of pubs, restaurants and cafes, said a ban raised the prospect of “serious economic harm” to venues. “You only have to look back to the significant pub closures we saw after the indoor smoking ban to see the potential impact it could have,” she said.

Nicholls called on the government to hold a “detailed conversation” with affected parties on the potential impact of such a ban before any legislation was put in place.

William Lees-Jones, the head of JW Lees Brewery, which owns and operates 150 pubs, inns and hotels mainly in north-west England and north Wales, said the idea was a “bolt from the blue” that had not been discussed with industry. He said it would be “really bad for business” and could “shut a lot of pubs”.

“People who smoke are pretty determined and will walk 10 yards down the road and smoke there, which will annoy other people,” he said.

Clive Watson, the chair of the Inda Pubs group, called it “a bonkers idea”, adding: “Surely, after all the pub industry has been through, we should be allowed a period of stability?”

Tim Martin, the chair of JD Wetherspoon, said he did not think a ban would have a “big effect” on business, but added: “The question is whether the government should interfere in individual liberties, where danger is involved.”

Dr Layla McCay, the director of policy at the NHS Confederation, said she was “heartened” to see progress being made on abolishing smoking. She told BBC Radio 4’s Today programme: “It is absolutely the health challenge of our time. It’s the leading cause of preventable illness in the UK, so we are heartened to see that progress is being made and that the intention is moving forward to really address one of Britain’s main drivers of health inequalities.”

While a majority of Conservative MPs voted for Sunak’s gradual smoking ban in April, a number opposed the plan. Patel, the former home secretary, argued on Wednesday that the outdoor smoking curbs would harm businesses and potentially endanger public safety if police resources were used to enforce it.

Robert Jenrick, also standing to be Tory leader, tweeted of Starmer: “This man does not understand our country.”

The Liberal Democrats said the plans must be balanced against any potential impact on hospitality venues.

YouGov polling carried out on Thursday showed the public tended to support the plan, with 58% of people saying they backed the idea, against 35% who did not. The figures were virtually identical for Conservative voters.

A spokesperson for the Department of Health and Social Care said: “We do not comment on leaks. Smoking claims 80,000 lives a year, puts huge pressure on our NHS, and costs taxpayers billions. We are determined to protect children and non-smokers from the harms of secondhand smoking. We’re considering a range of measures to finally make Britain smoke-free.”

After smoking in enclosed public places and workplaces was barred in 2007, according to the charity Action on Smoking and Health (Ash), in the year after there were 12,000 fewer overall admissions to hospitals in England, including a 12.3% drop in hospital admissions for childhood asthma.