Millions of women have been caught up in government efforts to cut the costs of paying for the state pension and to equalise the age at which men and women receive the state pension.
That effort goes back decades, so to help understand the issue here is some background.
How did we get here?
From 1948 for more than 60 years men received their state pension at 65 and women at the age of 60.
But over the years it was argued that the difference was unfair, as women had a longer life expectancy than men.
So under the 1995 Pensions Act a timetable was drawn up to equalise the age at which men and women could draw their state pension.
The plan was to raise the qualifying age for women to 65 and to phase in that change from 2010 to 2020.
But the coalition government of 2010 decided to accelerate that timetable, arguing that the state pension was becoming unaffordable.
Under the 2011 Pensions Act the new qualifying age of 65 for women was bought forward to 2018.
Also, the qualifying age for men and women would be raised to 66 by October 2020.
Those changes were expected to save £30bn.
Who is affected?
In total around 2.6 million women were affected by the 2011 changes. While some of them had time to adapt to a longer working life, for others the change came as a shock.
In particular, around 300,000 women born between December 1953 and October 1954 and getting close to their state pension age, were made to wait an extra 18 months.
For women who were not aware of the 1995 changes, the shock was more severe. They had been expecting to retire at 60, but discovered that they would have to wait years longer.
They complained they had not been given time to adjust to the new retirement age and also that the changes in 1995 and 2011 had not been clearly communicated.
Women Against State Pension Inequality (Waspi) emerged to campaign over those issues.
Waspi wants compensation for the "unfair" way the changes of 1995 and 2011 were implemented.
It wants payments for those who have already reached the state retirement age, plus extra income for those still awaiting their state pension.
But it is not asking for women's retirement age to return to 60.
Critics of Waspi say it is not clear how much their demands would cost.
The government has said it has already committed £1bn to mitigate the impact of the changes, ensuring that no one would see their pension date move by more than 18 months. It has said consistently that there will not be any further changes to the policy.
Another campaign group, Backto60, won the right to have the government's actions ruled on by the High Court, but they lost the case.