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.

In 1978, despite the passage of legislation to promote equal pay, women's relative position in the UK was still worse than in Italy, France, Germany, or the Benelux countries in 1972.

Jobs which had previously been classed as manual or administrative/clerical would be brought together under one pay scale and one set of terms and conditions.

The implementation of Single Status in local government led to many claims being brought by employees as they sought compensation for past pay disparity.