The confederation was founded in December 1890 as the Federation of Engineering and Shipbuilding Trades by small craft unions, on the initiative of Robert Knight of the United Society of Boilermakers and Iron and Steel Shipbuilders, primarily in response to the formation of a National Federation of Shipbuilders and Engineers by employers. By 1895, sixteen unions were affiliated, with a total membership of 150,000. However, the prominent Amalgamated Society of Engineers refused to join. The ASE finally joined in 1905 but, failing to persuade the other members to unite with it in a single industrial union, withdrew again in 1914. Meanwhile, unions representing unskilled workers were initially excluded; the National Amalgamated Union of Labour was finally admitted in 1908, and the National Union of Gasworkers and General Labourers in 1910, and only after they had given assurances that they would permit the craft unions to retain a leading role in the organisation. Because it would not sign a similar agreement, the Workers' Union was never admitted. In its early years, the Federation focussed on resolving demarcation disputes, but it soon concentrated on making national agreements for the engineering and shipbuilding industries, allowing the largest union in each trade to take the lead in negotiations. The confederation adopted its current form and name in 1936. From 1941, the CSEU co-operated with the National Union of Foundry Workers and the Amalgamated Engineering Union in the National Engineering Joint Trades Movement, convincing these two unions to affiliate in 1944 and 1946 respectively. The confederation then represented the vast majority of unionised workers in the relevant industries. By 1977, the CSEU had 23 affiliates and 2.4 million members, with most workers organised in the relevant sections of the Transport and General Workers Union, General and Municipal Workers Union and Electrical, Electronic, Telecommunications and Plumbing Union. Members in 1979 were:
In 1989, membership was still 22 affiliates and 2 million members but, by 2001, this had fallen to 1.2 million members, and a process of union mergers has greatly reduced the number of affiliated unions and the prominence of the organisation. All current affiliates are also members of the Trades Union Congress. By 2017 the union had no direct members and was functioning as a federation of the Unite, GMB, Community, Prospect and UCATT trade unions. Since the merger of UCATT into Unite the number of member unions has fallen to four.
Current members
Community
GMB
Prospect
Union of Construction, Allied Trades and Technicians
