Representatives from the BackTo60 campaign group have been back in court to challenge the government's handling of the rise in the women's state pension age.
The campaigners are appealing against a ruling by judges in October 2019, which rejected claims of discrimination.
The rise in the pension age was accelerated in 2011, which meant that many women had little time to prepare for an even longer wait for the pension.
Leading the case for the campaigners, Michael Mansfield QC has told the appeal hearing that: 'This cohort are bearing the brunt and shouldering the onerous situations that arise after the statutes come into force.
'This has been catastrophic and their lives have been totally fractured having to face a situation of this kind.'
Sir James Eadie QC, representing the Department for Work and Pensions (DWP), has countered that the must be economically viable, and there is no justification to have different pension ages for men and women, particularly with women living for longer than men.
The large number of women who saw their increased has been represented by two women in their 60s, Julie Delve and Karen Glynn who mounted the challenge to the Court of Appeal, with support from the BackTo60 campaign group.
Around 3.8 million women born in the 1950s have been impacted. BackTo60 maintains that the women were not given enough notice to prepare for up to six years without their state pension.
The appeal has been heard over two days and the judges are expected to give their ruling at a later date.
BackTo60 has long campaigned on the premise that pay for women was often lower than that for men and many women took breaks from work to bring up children. This means that not receiving their pension at 60 has had a disproportionately harsh effect, BackTo60 argued.
The plight of those affected was initially taken up by a group called Waspi - Women Against State Pension Inequality - which launched its campaign in 2015.
The initial verdict was delivered in October 2019 after a two-day judicial review at the High Court in June 2019.
The Court found in favour of the government at that time, with the judges saying: 'There was no direct discrimination on grounds of sex, because this legislation does not treat women less favourably than men in law.
'Rather it equalises a historic asymmetry between men and women, and thereby corrects historic direct discrimination against men.'
The DWP had strongly opposed the original case. Governments have long argued that the age rise was justified on the grounds of intergenerational fairness, and addresses inequalities between men and women's state pension ages.
A DWP spokesperson told us at the time of the original verdict: 'The government decided more than 20 years ago that it was going to make the state pension age the same for men and women as a long-overdue move towards gender equality and this has been clearly communicated.
'People are living longer, so we need to raise the age at which all of us can draw a state pension so it's sustainable now and for future generations.'
Until 2010, women received their state pension at age 60, while men received theirs at age 65.
A phased timetable rapidly raised the state pension age for women from 60 to 65 between 2010 and 2018.
It's currently 65 for both men and women, increasing to 66 by October 2020. The state pension age is then scheduled to rise to 67 between 2026 and 2028.
The age you'll start to receive the state pension will depend on when you were born.
You can use our state pension age calculator to work out when you're likely to qualify.