A trigger cause for the introduction of the legislation was the 1968 Ford sewing machinists strike ,  though the legislation also paved the way for the UK's entry to the European Community, helping to bring it towards conformity with Article 141 of the Treaty of Rome, which says that 'each Member State shall ensure that the principle of equal pay for male and female workers for equal work or work of equal value is applied.'.   The Act came into force on 29 December 1975. The term pay is interpreted in a broad sense to include, on top of wages, things like holidays, pension rights, company perks and some kinds of bonuses. The legislation has been amended on a number of recent occasions to incorporate a simplified approach under European Union law that is common to all member states. The 1970 Act only dealt with equal pay for the same work but in 1975 the EU directive on Equal Pay was passed based on article 119.
The list goes on and on and on -- go check out your own city or state on the NPWF website -- but the point is that the money being withheld from women is not a trivial matter. The situation is especially dire for the more than million families where the woman is the breadwinner. Thirty-one percent of these families fall below the poverty line .
The gap isn't getting any smaller. According to the Institute for Women's Policy Research , if things continue to go the way they are going, it will take another 45 years for women to catch up to men .