A new NHS-style social care system for England could take decades to be implemented, economist Sir Andrew Dilnot has told the BBC.

Sir Andrew, who led a commission proposing reform of the system 15 years ago, said Prime Minister Andy Burnham appeared to want social care to be completely free, including residential costs.

He told BBC Radio 4’s Today programme the cost of such a scheme would be “very substantial”.

And with Burnham promising to put his plans before voters at the next general election, Sir Andrew said change “is now further away”.

Adult social care provides state support to help people live more independently, including assistance at home.

However, unlike the NHS, social care is not free at the point of use in England, leaving some people facing huge bills.

In an interview with the BBC’s Sunday with Laura Kuenssberg, Burnham suggested his proposals for social care would mean “everyone contributes, everyone is covered” and refused to rule out tax rises to fund such a system.

He promised to set out more details of his vision in his conference speech on Tuesday.

However, he suggested any proposals would not be implemented before the next general election, as he wanted to stick to the commitments in Labour’s 2024 election manifesto, which included a promise not to increase national insurance, income tax or VAT.

Labour MP and former minister Darren Jones told Laura Kuenssberg that scrapping the pensions triple lock was an “option that the government should consider alongside others” in order to fund social care reforms.

The triple lock pension policy guarantees that the state pension will increase by either average wage growth, inflation or 2.5% – whichever is highest – and keeping it in place is also a Labour manifesto pledge.

But Helen Miller, director of the Institute for Fiscal Studies think tank, said scrapping the triple lock would not be enough to pay for social care and tax rises would also probably be needed.

The next general election is not due until August 2029, although Burnham could choose to call one earlier.

Sir Andrew told the BBC change on social care “is now further away” than had been implied when Burnham first promised a new national care service for England in a speech in July, shortly after he became prime minister.

He pointed out that if proposals are included in Labour’s 2029 election manifesto, that would be 30 years after Sir Tony Blair launched a royal commission on social care and more than 15 years since his own commission reported back.

By promising an NHS-style system for social care, Sir Andrew said the PM was implying it would be “entirely free”.

In England and Northern Ireland, people with assets worth more than £23,250 – including their home – are not currently entitled to help with care costs from their council.

In Wales, social care is also means-tested.

In Scotland, state-funded personal care is offered to all adults who are assessed as needing help with tasks including eating and bathing.

However, this does not include accommodation, food and everyday living costs, which are subject to means testing.

Sir Andrew said a Scottish-style system would still leave people in residential care facing “very substantial bills”, which Burnham has said he wants to avoid.

The Health Foundation has estimated a universal social care system in England, with the government funding all support, could cost around £18.5bn a year.

On Sunday, Burnham said he believed the costs would be lower than this but he has not set out how he would fund his plans.

Sir Andrew said he believed an NHS-style social care system could costs “well in excess of £18bn”, although a Scottish model could cost half this figure.

He added: “I also think that there was an indication in what [Burnham] said that he’s imagining something that could take many years, even many decades before it came to fruition.”

Sir Andrew said he would “love to see such a scheme”, where all social care is government-funded, but “the cost would become very, very large”.

He added that a system where the amount people must pay towards their care is capped, “could still work well for elderly people”.

Sir Andrew’s own commission proposed a lifetime cap of £35,000.

The report’s recommendations were accepted by the Conservative-Liberal Democrat coalition government, led by David Cameron.

However, the implementation of the cap was delayed to 2020, with Cameron blaming pressure on the public finances, and the idea was eventually dropped by subsequent Conservative governments.

Other proposals to reform the system have also failed, with Theresa May’s Conservative government scrapping plans to make people receiving care at home pay the full costs if they were worth at least £100,000, after this was branded a “dementia tax” by opponents.

Meanwhile, when he was health secretary in Gordon Brown’s government, Burnham’s plan for a national care service suggested this could be paid for through a compulsory contribution from people’s estates after they die.

The idea was branded a “death tax” by Labour’s opponents and the proposals went no further after the party lost the 2010 general election.

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