The firm’s record on equal pay was revealed as thousands of employers with over 250 staff were forced to published their gender pay gap figures for the first time.

The Government hopes this will help to shine a light on the barriers preventing women from reaching the top.

Construction ranks as one of the worst industry’s for pay inequality with women paid 36% less than men on average.

The first returns by leading main contractors reveals Laing O’Rourke is way ahead on pay equality with women on average paid just under 9% less than men.

Companies had to file data based on a “snapshot” of their payroll taken on 5 April 2017.

The discrepancy among major players is widened because fewer women are among the top earners in the industry.

This appears to have impacted BAM Construct which recorded the highest pay gap and women accounting for 68% of the lowest quartile of earners in its workforce.

The listing of the top 30 main contractors compiled by the Enquirer is ranked by the median, which gives a good sense of where a company is overall, the mean figures will include the outliers with large salaries.

The mean hourly rate is the average hourly wage across the entire organisation so the mean gender pay gap is a measure of the difference between women’s mean hourly wages and men’s mean hourly wages.

The median hourly rate is calculated by ranking all employees from the highest paid to the lowest paid, and taking the hourly wage of the person in the middle; so the median gender pay gap is the difference between women’s median hourly wage (the middle paid woman) and men’s median hourly wage (the middle paid man).