In 1970, the Draughtsmen's and Allied Technicians' Association (DATA), Amalgamated Union of Engineering and Foundry Workers (AUEFW) and Constructional Engineering Union (CEU) amalgamated to form the Amalgamated Union of Engineering Workers (AUEW). The former members of DATA formed the Technical and Supervisory Section of the new union. At the 1973 Representative Council Conference it was agreed to rename it the Technical, Administrative and Supervisory Section (TASS).
In 1985, after considerable problems within the AUEW, TASS broke away to become an independent union.
TASS absorbed the National Union of Gold, Silver and Allied Trades (NUGSAT) in 1981, the National Union of Sheet Metal Workers, Coppersmiths, Heating and Domestic Engineers in 1983, the Association of Patternmakers and Allied Craftsmen in 1984, the Tobacco Workers' Union in 1986, and the National Society of Metal Mechanics in 1987.
In 1988 it merged with the Association of Scientific, Technical and Managerial Staffs (ASTMS) to become the Manufacturing Science and Finance Union (MSF). MSF in turn merged with the AEEU to form Amicus in 2002. Ironically, this resulted in TASS and the former AUEW (by then part of the AEEU) being re-united within one union.