Women affected by changes to the state pension age are due to hear the outcome of their high court fight against the government.

Nearly 4 million women born in the 1950s have been affected by the changes, which have raised the state pension age from 60 to as high as 66. It has been increased by successive governments in an attempt to ensure “pension age equalisation”, so that women’s state pension age matches that of men.

Julie Delve, 61, and Karen Glynn, 63, have taken the Department for Work and Pensions (DWP) to court, arguing that raising their pension age “unlawfully discriminated against them on the grounds of age, sex, and age and sex combined”.

Delve and Glynn, supported by the campaign group BackTo60, also claim that they were not given adequate notice in order to be able to adjust to the changes. Lord Justice Irwin and Mrs Justice Whipple are due to deliver their judgment on the lawfulness of the changes on Thursday morning.

Addressing a court packed with supporters at a hearing in June, Michael Mansfield QC said “roughly 3.8 million” women had been affected by the changes.

The barrister said raising the state pension age discriminated against women born after 1950 on the grounds of their age, and also put women “at a particular disadvantage to men”. He submitted that “the claimants and many other women born in the 1950s” were not told about the changes “until shortly before their expected state pension age at 60”, which caused “significant detriments” to many of them.

He said women born in the 1950s had already suffered “considerable inequalities in the workplace”, which he said were the result of “historical factors and social expectations”.

Sir James Eadie QC, representing the DWP, argued that the changes were intended “to equalise the state pension age between the sexes” and “to ensure intergenerational fairness as between those in receipt of state pensions and the younger taxpayers funding them”.

He said the aim of raising the pension age to 66 was also to “make pensions affordable ... and to control government expenditure at a time of great pressure on public finances”.

Eadie submitted that the government took extensive steps to notify women of the change to their state pension age, and that “personal notification would have been very difficult if not impossible prior to 2003”. He said the changes “pursue obviously legitimate aims”, and that they “strike a balance between the public interest and the claimants’ interests”.