Maria Miller, the women and equalities minister, has urged government departments and companies to publish details of the pay gap between men and women as part of a government action plan on women and the economy.
In a three-point plan timed to coincide with Equal Pay Day – the single day on which women, in effect, "stop being paid" for the year because of the gender pay gap – the minister urged companies to promote more women on to boards amid signs that efforts to improve workplace equality are stalling.
Having mothballed section 78 of the Equality Act, which would have forced companies to report their gender pay gap in 2010, the government continues to insist on voluntary action. "I don't believe government intervention will work," Miller said. "Legislation alone is simply not enough … We need cultural change"
So far 130 large employers have signed up to the voluntary Think, Act, Report code, which encourages them to publish whatever gender equality data they think fit. Tesco and BT are among the handful of FTSE 100 companies that publish detailed gender pay gap statistics.
Perhaps more embarrassing for the government is that few of its own departments do the same. Miller has written to all Cabinet ministers asking them to ensure their departments publish their own gender equality information, saying: "I want government to lead by example."
Earlier this month, the ONS revealed that the overall median gender pay gap in the civil service is 13.6%, compared to the national average of 15%. The difference is even bigger for women working part time, who earn 35% less per hour than men working full time, according to a TUC analysis of official figures.
The chancellor, George Osborne, introduced the action plan by saying there was still a "long way to go" on achieving boardroom equality.
Women should make up 25% of all boardroom seats by 2015 under targets set two years ago by the government taskforce led by Lord Mervyn Davies. Since then, the percentage of women on FTSE 100 boardrooms has risen from 12% to 19% and to 15% on FTSE 250 boards.
However, Lord Davies admitted recently that the pace of change – shown by the percentage of new appointments given to women – has slowed or "been towards the bottom end of this range".
Miller, however, said just 66 women had to be appointed on FTSE 100 boardrooms in the next year to meet the target. Suggesting she would be "astonished" if that target isn't met, she add, "When you really break it down the size of the challenge here is handleable."However, Ann Francke, the Chartered Management Institute (CMI) chief executive, said: "Progress has been made to get more women on boards and to reduce the gender pay gap, but this has been all too small and all too slow. There is a drop-off in the female talent pipeline and changing this will be the only way we will ever see equal representation in UK boardrooms."
A study by the CMI revealed that while 60% of junior managers are female, the figure is just 20% among senior staff. The report blamed "masculine" workplaces, lack of flexibility from employers and a phenomenon it dubbed "sorry skirts" – women's tendency to apologise more often than men.
Separately, a study by the TUC found that the gender pay gap in some jobs is three times bigger than the £5,000 average. Female health professionals had the biggest gap, earning £16,000 a year less than their male counterparts. The gender pay gap across the private sector is 19.9%, far higher than the 13.6% pay gap in the public sector, said the TUC.
