The pay gap between genders in the public sector is the subject of the latest Unison campaign.
According to the union, the salary difference between men and women working in the same public sector pay band is the equivalent of the females working from October 30th until the end of the year for free.
Thus Unison has made October 30th Women's No Pay Day.
Dave Prentis, the Unison general secretary, remarked that pressure on the government from the organisation last year resulted in the release of £500 million to local authorities in order to address the issue.
"The government must change the law to cut the time it takes for legal action. At the moment, it takes years, is costly and, in the meantime, women remain underpaid," he said.
There are currently 33,000 equal pay claims lodged against public sector employers.
A rise in the minimum wage was recently called for by the Institute for Public Policy Research.