[2] It merged with the competing National Society of Coppersmiths, Braziers and Metal Workers in 1959, renaming itself the National Union of Sheet Metal Workers and Coppersmiths.

Following its 1967 merger with the Heating and Domestic Engineers' Union, it took its final, lengthy name.

[3] The last independent union for sheet metal workers, the Birmingham and Midland Sheet Metal Workers' Society, finally merged into the union in 1973.

[4] The union approved an offer to join the Amalgamated Union of Engineering Workers' Engineering Section in 1979,[1] but this did not go ahead and instead, in 1983, it merged into the Technical, Administrative and Supervisory Section.

[3] The union sponsored a Labour Party candidate in the 1979 general election:[5]