Pregnant Then Screwed took the government to court, claiming the way the Self-Employment Income Support Scheme (SEISS) grant was calculated discriminated against women.

The group, with support from Doughty Street Chambers and law firm Leigh Day, took chancellor Rishi Sunak to the high court on 21 January. The second claimant was Kerry Chamberlain, a self-employed energy analyst and mother of three young children.

SEISS was introduced by Sunak in April 2020 to support self-employed workers whose trade had been adversely affected by Covid-19.

But the eligibility conditions and calculation method do not exempt periods of maternity leave. This means women who have taken time off to have a baby in the past three years receive a lower grant payment than other workers.

Pregnant Then Screwed asked the chancellor to take immediate steps to change the SEISS so that time taken for maternity leave is discounted when average earnings are calculated.

But the chancellor’s response was: “for all sorts of reasons people have ups and downs and variations in their earnings, whether through maternity, ill-health or others.’’ In an official response, Sunak’s legal team compared maternity leave to taking a sabbatical.

Pregnant Then Screwed said about 69,200 women had been impacted. It begun legal proceedings in July.

But the court dismissed the case. Mrs Justice Whipple said she did not deem the matter to be indirectly discriminatory and that it imposed no hidden barriers to eligibility.

The judgement said: “I am not therefore persuaded that there is any indirect discrimination, approaching the matter on a conventional analysis. The measure imposes no hidden barriers to eligibility.

“So far as quantum of payment is concerned there is no hidden barrier either: quantum is based on past (average) trading profits, which are a matter of past fact. The same rule applies to all and it is no harder for a woman who has been on maternity leave to qualify or calculate their payment, than someone who has not. The fact that some claimants will receive lower payments than others reflects the fact of lower earnings in past years.”

Pregnant Then Screwed said there were “serious legal errors” in the verdict and that it found the judgment to be “fundamentally flawed.” The group is considering options for appeal.

The group said in a statement: “We are, of course, deeply concerned for the vulnerable new mothers who have had a much-reduced payment compared to their male and childless counterparts, and are now really struggling over the winter period. How a judge could consider this not to be discrimination has really shocked all of us. Thank you to everyone who offered their support with this case. We hope that people will continue to support us if we go to appeal.”