Theresa May could help millions of women in their Fifties struggling with changes to their State Pension Age for just a quarter of the quoted price, according to SNP MPs.

Conservative ministers have said that reversing the reforms would cost more than £30billion.

But new research by Landman Economics, commissioned by the SNP, suggests much of the money could be found from within the pension system, meaning just an extra £8bn is needed.

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The SNP says that the findings show that the Prime Minister should act immediately.

The row centres on 2.6 million women born in the 1950s, who campaigners claim were never properly informed the changes to their pension age.

Some now face an uncertain future, waiting years longer than expected to receive their pension.

Landman Economics says it could cost an extra £8bn to return to the original timetable set out in the 1995 Pensions Act.

It points to the National Insurance Fund (NIF), which is forecast to have a £26bn surplus this year.

Ian Blackford MP, the SNP’s pensions spokesman, said: “A pension is not a privilege, it is an entitlement and yet millions of women born in the 1950s are struggling to make ends meet because they are being denied their pension – many women are facing real hardship and they need action now.

“The Tories have tried to wash their hands of this crisis but that is simply not good enough which is why the SNP decided to do the work for them. Our independently researched report reveals the five options immediately available to the UK Government to deliver dignity in retirement for the 2.6m women affected and ensure that the mistakes of the past are corrected.

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“(One) would allow a return to the 1995 Pensions Act and would slow the rise of the state pension age for women to reach 65 by 2021. At £8 billion, this option is the second most expensive but it pales in comparison to the £30 billion figure often used by Tory politicians attempting to absolve themselves of any responsibility.

“The National Insurance Fund is billions of pounds in surplus and can be only be used to pay for contributory benefits such as the State Pension.

“Millions of pensioners, workers and their employers have no idea that the money they are paying in National Insurance contributions every month is not being used to pay higher pensions and benefits.”

SNP MP Mhairi Black, who has campaigned on the issue, said: “Not only have these women had their retirement plans completely shattered, they were also badly let down by a UK Government that failed to adequately inform them of the changes.”

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She added: "£8bn is not a small amount of money but it is a drop in the ocean for this Tory Government that thinks nothing of spending £167bn on their nuclear-obsession by renewing the obsolete Trident weapons system – that’s twenty times the cost of ending pension inequality for these women.”

“If the Prime Minister is to live up to her rhetoric of working “not for the privileged few” it is time to end this inequality and deliver for the women of the 1950s.”