Women take home on average 18% less an hour

Figures released by the equality body suggest only one in five employers has conducted a pay audit.

The purpose of the audits, which are voluntary, is to ensure that women are not being paid less than men.

According to the government, women working full time are paid, on average, 82% of men's average earnings.

Julie Mellor, chair of the Equal Opportunities Commission, said conducting a gender pay audit made good business sense.

"The majority of employers who have done pay reviews said they did it because it is good practice and makes business sense to check they are rewarding staff fairly.

"And in the long run it will help protect employers against costly pay discrimination claims."

The Commission said that if employers continued to resist carrying out reviews, it might have to conclude that further legislation was the only way to guarantee a fair deal for women at work.