Changes to the state pension age for women are at the centre of a landmark discrimination case brought against the government.

The High Court is due to start hearing a case brought by two claimants who say that raising their pension age discriminated against them on the grounds of their age and their sex.

They also allege they were not properly informed of the changes in time to adjust.

Their barrister, Michael Mansfield QC, will argue that changes introduced by successive governments, affecting almost four million women, are unlawful.

The state pension age was increased, most recently in 2011, in an attempt to ensure "pension age equalisation", so women's pension age matched that of men.


But at an earlier hearing in November, Mr Mansfield said some of the women affected were given as little as 18 months' notice and left in a "powerless" position.

The court also heard then that the changes meant that £5.3bn had been "saved from women".

Lawyers for the Department for Work and Pensions, which is defending the claim, said the changes to the state pension age were made to ensure "inter-generational fairness".

In a statement ahead of the hearing, a spokesman for the department said: "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.

"We need to raise the age at which all of us can draw a state pension so it is sustainable now and for future generations."