Liberal Democrat leader Ed Davey is urging the Labour government to “invest more in the NHS or accept continued decline”.

Sir Ed is calling for a “budget for the NHS” in October, with more investment in hospitals and training doctors, nurses and dentists.

The party says the NHS needs £3.7bn a year extra in day-to-day spending, and a further £1.1bn a year for investment.

The NHS and social care are the main focuses of the party’s autumn conference in Brighton.

The conference comes in the week a report by surgeon and independent peer Lord Darzi described the NHS as a “broken system” that was in “serious trouble”.

The former Labour minister’s report said the NHS had been “starved” of funding for hospital repairs and faced a shortfall of £37bn of investment.

In response, Prime Minister Sir Keir Starmer promised a 10-year plan for the NHS, but he said there would be no extra funding without reform.

The Lib Dem leader is using his party’s conference to say reform on its own will not be enough, ahead of Chancellor Rachel Reeves’s autumn budget.

“We need to see a budget for the NHS, with investment to fix our crumbling hospitals, replace ageing equipment and ensure people can see a GP or dentist when they need to,” Sir Ed said.

“The government can only deliver the improvements that patients urgently need with additional investment in the NHS alongside reform.

“The government faces a stark choice: invest more in the NHS or accept continued decline.”

Sir Ed told the BBC’s Sunday with Laura Kuenssberg programme that addressing social care was “the most important part” of health care reform.

“I don’t believe you can sort out some of the problems in our hospitals where people can’t get discharged, where people keep going back, and there’s a revolving door, unless you sort out social care,” he said.

“And that means better care homes, more care staff, better domiciliary care services, paying care workers more.”

The Lib Dems were in a sunny mood befitting of the weather in Brighton, as they celebrated winning 72 seats – their most-ever MPs – in July’s general election.

Sir Ed – who carried out a series of daring stunts during the election campaign – opened the conference in eye-catching fashion, by riding a jet ski through Brighton Marina.

Now the third-largest party in the House of Commons, the Lib Dems are positioning themselves as a “constructive opposition”.

But this conference is also about carving out dividing lines with Labour, which won a huge majority in the general election.

Sir Ed told the BBC the Lib Dems “absolutely will challenge the government where we disagree with them” and pledged to be a “better opposition than the Conservatives”.

At a fringe event, the new MP for Cheadle, Tom Morrison, said “empowering communities” and pushing for reform of social care were ways the party could distinguish itself from Labour.

Another newly elected Lib Dem MP, Paul Kohler, said his party needed to “challenge the authoritarian side of Labour” and propose progressive solutions to problems, such as the overcrowding crisis in prisons.

But they all agreed the Conservatives were still their main opponents in most election battlegrounds.

In a speech on day one of the conference, chief whip Wendy Chamberlain claimed the Liberal Democrats were “the party of the NHS and care”.

The MP said the Lib Dems will use their boosted numbers in Parliament to call for urgent improvement to NHS services.

The Lib Dems put the NHS and social care at the heart of its election manifesto.

When asked how they would pay for their policies, the party said the extra £1.1bn of capital investment would come from borrowing.

The additional £3.7bn a year on day-to-day spending would be raised through closing loopholes in capital gains tax, the party said.

The Lib Dems claim only 0.1% of the population would see a tax rise under their plans to fund this spending top-up.

In her speech, Chamberlain was critical of the Conservatives, who the Lib Dems took most of their seats from in the general election.

But she also lambasted the SNP, who she accused of taking voters in Scotland for granted and using its platform in Parliament to “grandstand”.

“The SNP has pursued a decade of division and the people of Scotland have paid the price,” she said.

She said the Lib Dems have a chance to “kick the SNP out of power” at the next set of elections to the Scottish Parliament in 2026.

On Sunday, the Lib Dems turned their focus to education, with education spokesperson Munira Wilson giving a speech calling for an expansion of free school meals to all children in poverty.

The conference will continue in Brighton until Tuesday, when Sir Ed will make a speech to the party faithful.