The NASUWT is a TUC-affiliated trade union representing teachers, including headteachers, throughout the United Kingdom. The early years 1919–1976; breakaway and the formation of a new union The origins of the NASUWT can be traced back to the formation of the National Association of Men Teachers (NAMT) in 1919, which formed as a group within the National Union of Teachers (NUT) to promote the interests of male teachers. The formation of the NAMT was in response to an NUT referendum the same year, approving the principle of equal pay for women. The NAMT continued its campaign to further the interests of male teachers, changing its name in 1920 to the National Association of Schoolmasters (NAS). In 1922 the NAS broke away from the NUT and established its own organisation. The secession came about indirectly following a decision at the NAS Conference that year, to prohibit NAS members from continuing to also be members of the NUT after the 31 December 1922. The NAS aimed to recruit every schoolmaster into the NAS, to safeguard and promote the interests of male teachers, to ensure recognition of the social and economic responsibilities of male teachers, and to ensure the representation of schoolmasters on matters concerned with education, with both the local education authorities (LEAs) and government. The NAS also maintained that all boys over the age of seven should be taught mainly by men and that schoolmasters should not serve under women heads. As the secondary education sector expanded, the NAS built its organisation among male secondary teachers, it adopted the methods of collective bargaining and militant industrial action in pursuing a narrow range of pay and conditions issues related to the interests of full-time male 'career teachers'. By the 1960s, the union was still opposed to admitting women as members, but it was concerned that the unions open to women teachers were all hostile to its objectives. As a result, it encouraged the formation of the Union of Women Teachers (UWT). In 1976 the NAS merged with the Union of Women Teachers (UWT) and the Scottish Schoolmasters' Association (SSA). The merger was largely a consequence of the Sex Discrimination Act 1975, which made it unlawful to exclude from membership on grounds of gender. It then became the National Association of Schoolmasters/Union of Women Teachers (NAS/UWT). The 'slash' separating the two sections of the union was later dropped and the name usually appeared