THREE-QUARTERS of employed mothers have suffered pregnancy and maternity discrimination in the workplace, a “worrying” new study revealed yesterday.

A survey of 3,000 women showed that 77 per cent were kept in the dark about promotion opportunities, harassed by colleagues, denied training, pressured to leave and even threatened with the sack.

But only one in four had raised problems with their boss, and less than 1 per cent took their case to an employment tribunal, the Equalities and Human Rights Commission (EHRC) report said.

The £1,200 tribunal fees are a “barrier” to justice, said the commission, as are a lack of information provision and the considerable stress involved in lodging a claim in court.

Sex discrimination cases are down by 76 per cent and pregnancy-related cases had dropped by half since the tribunal fees were introduced in 2013, according to the survey.

Shadow women and equalities minister Kate Green said: “The Tories promised the most family-friendly government ever, but … underpinning the rise in pregnancy discrimination is the lack of access to justice under [the Tories].

“The government must bring forward plans urgently to raise awareness among employers of their legal obligations to pregnant workers and a comprehensive strategy for eradicating maternity discrimination.”

TUC general secretary Frances O’Grady called it “disgraceful” that thousands of women are forced out of jobs each year and struggle to have their rights enforced.

Women should also have six months to bring cases to a tribunal, rather than the current three-month time limit, the commission recommended.

It pressed the government, employers, regulators and charities to urgently tackle “outdated practices” at work, including banning employers from asking job interviewees about any plans to have children.

A quarter of the 3,000 employers surveyed said that they thought it was reasonable to question women candidates about any childbearing plans.

Three-quarters of mothers who had unsuccessful job interviews while pregnant said they believe the employer did not hire them for that reason.

Tory MP Maria Miller, who chairs the Commons women and equalities committee, said the panel of MPs was opening an inquiry into the findings.