MOTHERS in Britain will be working for free for the rest of the year, a report by campaign group Pregnant Then Screwed finds.

Today is Mums Equal Pay Day — the point mothers start working for free compared to their male counterparts.

The earning gap between mothers and fathers widens over the first 20 years after a mother returns to work, where they earn 30 per cent less than similarly educated fathers, research by the Institute for Fiscal Studies found.

Analysis from 2016 also revealed that women who have children before the age of 33 are paid 15 per cent less than their childless peers and that that 54,000 were being pushed out of their jobs due to pregnancy and maternity discrimination.

Pregnant Then Screwed founder Joeli Brearley warned that motherhood was “the key driver” of the gender pay gap.

She said: “Employers have a responsibility to support pregnant women and new mums in the workplace.

“Mums Equal Pay Day is a chance for us to shout about the specific challenges mothers encounter and say enough is enough.”

The campaign group is calling on the government and employers to do more for fairer access to labour including free universal childcare, legislation encouraging equal share of domestic duties and flexible working as standard.

Fawcett Society’s Sam Smethers said not utilising a large percentage of the workforce makes “absolutely no economic sense.”

She added: “It is in all of our interest to create a labour market and a society that facilitates women being mothers and having a successful career.”