The Government watchdog is due to soon conclude its review into the way the changes were communicated, which could recommend an award of compensation.
Former Liberal Democrat leader Tim Farron, who is one of 43 MPs to write to the PHSO in support of the women, told i: “Many women made life-changing decisions based on a misconception the Government hadn’t bothered to correct and the ombudsman absolutely needs to get a move on and give them some answers.”
The affected women were born in the 1950s and made major decisions, such as retiring early, because they thought they could retire at the age of 60.
They say they were not given enough notice that their state pension age had been raised from 60 to 65 in 1995, in line with men. It subsequently increased to 66 for both sexes.
Insufficient notice about the changes left them with deep financial problems, they say.
Mr Farron said: “It is absolutely right that they are holding the Government to account for the terrible decision making that has led to such a gigantic injustice.”
The Women Against State Pension Inequality (Waspi) campaign, which represents some of the affected 1950s women, took their plight to the PHSO to investigate.
The ombudsman has found the Department for Work and Pensions (DWP) guilty of maladministration over the communication but said it only caused a limited level of injustice. Such a conclusion suggests the PHSO could recommend a compensation award on the lower end of the £100 to £10,000 scale.
Waspi’s lawyer John Halford, a partner at Bindmans, believes the PHSO should have found that the women suffered a greater level of injustice, including direct financial loss or lost opportunities.
After Waspi launched legal action against the PHSO, the watchdog is taking another look at its findings. There are hopes that more compensation could be recommended but there is no guarantee the ombudsman will alter the previous findings at all.
Mr Halford said it is “heartening” that over 40 MPs have contacted the PHSO to seek assurances that the investigation will be “completed not only promptly but fairly, taking full account of the impact of the DWP’s maladministration on 1950s-born women”.
Ian Lavery, the former Labour Party chairman, has also written to the PHSO in support of the women, telling i that “they face a historic injustice that needs to be put right”.
“These women have had their pensions taken away from them and it is time that they are given back what is rightfully theirs.
“Not only has this resulted in these woman having their pensions snatched away, but the emotional impact on them and their families has been immense. We can talk about numbers and how much this will cost, but ultimately it is their money and justice needs to be done.”
Green MP and former leader of the party Caroline Lucas said it was shocking that the injustice “remains unaddressed”.
“For many women it is already too late. It is vital that the ombudsman’s report does what is needed to provide Parliament with the information required to help secure fast, straightforward and significant action to address the injustice.”
The PHSO said: “We are confident that we have completed a fair and impartial investigation. As an independent Ombudsman, our duty is to provide the right outcome for all involved and make sure justice is achieved. Given the legal challenge brought against us, we have agreed to look again at part of our stage 2 report.
“We hope this cooperative approach will provide the quickest route to remedy for those affected and reduce the delay to the publication of our final report.”
The DWP said: “The Government decided over 25 years ago it was going to make the State Pension age the same for men and women.
“Both the High Court and Court of Appeal have supported the actions of the DWP under successive governments dating back to 1995 and the Supreme Court refused the claimants permission to appeal.”