costs, and in 1937 membership more than doubled, to 24,323. The British Pottery Manufacturers' Association began encouraging workers to join the union, hoping to prevent low-end manufacturers from undercutting its members. After World War II, the workforce in the British pottery industry declined, but the union increased membership density, and by 1975, 75.3% of pottery workers in the UK held membership of the union. During the 1950s, the union engaged with compulsory arbitration, but ended this in 1960, feeling it achieved little. In 1965, the union threatened to strike in order to improve wages. In 1970, the union became the Ceramic and Allied Trades Union, and it announced that it would recruit workers from all areas of the pottery industry, other than managers - this included areas such as clerical staff, electricians and maintenance workers, but these areas were already covered by other unions, and following various disputes, it largely withdrew from them. In 1975, the union signed a closed shop agreement with the British Pottery Manufacturers' Federation, although workers who did not wish to join could pay the equivalent amount to a charity. The agreement also established an approach to calculating wage increases, and gave workers two extra days holiday each year. This achieved most of the union's long-term aims. Employment in the pottery industry continued to decline, and by 2006, the union's membership was down to 7,239. In the hope of recruiting workers in other industries, it changed its name to Unity. In 2015, the union merged into the GMB. Election results The union sponsored its general secretary as a Labour Party candidate in several Parliamentary elections. Leadership General Secretaries 1906: Joseph Lovatt 1918: Samuel Clowes 1928: Arthur Hollins 1947: Harold Hewitt 1964: Alf Dulson 1975: Les Sillitoe 1980: Alf Clowes 1996: Geoff Bagnall 2012: Harry Hockaday Assistant General Secretaries 1947: Albert Goodwin 1955: Steve Hobson 1966: Les Sillitoe 1975: Alf Clowes 1980: Harold Hammersley Garry Oakes References External links 1906 establishments in the United Kingdom 2015 disestablishments in the United Kingdom Politics of Stoke-on-Trent Ceramics and pottery trade unions Trade unions established in 1906 Trade unions disestablished in 2015 GMB (trade union) amalgamations Trade unions based in Staffordshire