Kemi Badenoch is facing calls to get rid of the state pension triple lock in order to slash the welfare bill and win back younger voters, if the Conservatives return to power.

Reem Ibrahim, a spokeswoman for influential right wing think tank the Institute for Economic Affairs, said: “The triple lock is just completely unsustainable and it’s being spent on some of the wealthiest demographics in the country.”

Her call was echoed by Tory MP and former leadership contender Tom Tugendhat, who said young people had realised the “entire economy is now geared towards a bunch of people who are ageing”.

The Conservatives have ruled out scrapping the triple lock, which guarantees pensioners an increase in the state pension based on the highest of either inflation, wage growth or 2.5%, despite claims that the country can no longer afford it.

Labour and the Liberal Democrats are also committed to keeping the triple lock, while Reform UK has said it will announce its policy before the next election.

Speaking at a fringe meeting at the Conservative conference in Manchester, Ms Ibrahim branded the triple lock a “Ponzi scheme” – a type of investment fraud which pays profits to earlier investors with funds from more recent investors.

She also said millionaires should be stripped of the state pension – and payments increased to the least well-off pensioners.

“25% of pensioners are millionaires,” claimed Ms Ibrahim.

“I don’t believe Alan Sugar deserves a state pension. I think extremely wealthy people should not get a state pension because it is just a benefit.

“I would say the same thing about the winter fuel payment. If we are going to have long-term sustainability then we have to have these honest conversations.”

She was taking part in a debate about how the Conservatives can win back younger voters – a common theme at this year’s conference, with the majority of the party’s support coming from the over-65s at last year’s general election.

At another meeting, Tugendhat said young people were “drifting away” from the Conservatives because the party’s policies did not work for them.

“This is the logical series of outcomes for an economic system which has effectively become a Ponzi scheme for the old – that is what people are choosing against.

“Young people are looking at this and realising the entire economy is now geared towards a bunch of people who are ageing.

“You can see it in numerous different ways – you can see it in the way we are still defending the triple lock – when it is simply not sustainable.”

The Institute for Fiscal Studies estimates that the triple lock could push up state pension spending by anywhere between £5bn and £40bn a year by 2050.

In his conference speech, Shadow Chancellor Sir Mel Stride, unveiled plans to cut £23bn from the welfare budget if the Tories win power, with a crackdown on mental health-related benefits.

Shadow Business Secretary Andrew Griffith told a fringe meeting the Conservatives needed “bold” policies that would take voters by surprise at the next election.

Asked if ending the triple lock would fall into that category, he said: “Policy debates shouldn’t be debated at the extreme. That is one part of a very, very large welfare bill.”

He said Sir Mel had been right to focus on cuts to working age benefits, where people “have got the opportunity to re-enter the workforce, improve their mental health” rather than pensions.