GMB has its origins in the Gas Workers and General Union which was formed in 1889 by Will Thorne. Following the success of the Union's first battle in the campaign on working hours, workers flocked to join the new union and by 1911 its members numbered 77,000.
Also in 1889, on Tyneside, the National Amalgamated Union of Labour was formed and organised in the shipbuilding industry.
Together with the Municipal Employees Association and the National Federation of Women Workers, the four unions came together in 1924 to form the National Union of General and Municipal Workers. At that stage there were 359,000 members and although this figure dropped in the 1930s it picked up again in the war and during the years of full employment consensus.
Since 1924, there have been many more amalgamations including:
- the National Union of Water Works Employees
- the Scottish Metalworkers' Union
- the Salt & Chemical Workers' Union
- the Manchester Warehouse Employees' Association
- the Rubber, Plastics & Allied Workers' Union
- the Scottish Professional Footballers' Association
- the Coopers & Allied Workers of GB
- the Amalgamated Textile Workers
- the Scottish Lace & Textile Workers' Union
- the Greater London Staff Association
In 1982 the philosophies of general unionism and skilled craft unionism were brought together when the Amalgamated Society of Boilermakers, Shipwrights, Blacksmiths and Structural Workers (ASBSBSW) joined the General and Municipal Workers' Union to form the General, Municipal, Boilermakers and Allied Trade Union, (GMBATU).
The ASBSBSW itself was formed by amalgamating:
- United Society of Boilermakers
- The Shipwrights' Association
- The Blacksmiths' Society
APEX the Association of Professional, Executive, Clerical and Computer Staff was founded in 1890 when about a dozen men met in an office in the Strand and decided to form the Clerk's Union. As membership increased and spread across the country, the name was changed to The National Union of Clerks. In 1920, after rapid growth and the absorption of a number of other unions, the membership figure was around 40,000 and the name was again changed to The National Union of Clerks and Administrative Workers (NUCAW).
In 1940, the Association of Women Clerks and Secretaries transferred to NUCAW and a new title was agreed: The Clerical and Administrative Workers Union. Then, in 1972, arising from the spread of the union's influence, changes in office skills and the growing ability of the union to represent staff at all levels, it changed its title to the Association of Professional, Executive, Clerical and Computer Staff (APEX) and they joined GMB in 1989.
APEX accepted the Transfer of Engagements of the Automobile Association Staff and the General Accident Staff. Since the amalgamation, the Greater London Staff Association, who earlier transferred to GMB, joined the APEX Partnership and the National Union of Labour Organisers and Legal Aid Staff Association also transferred to APEX.
NUTGW the National Union of Tailors & Garment Workers joined the GMB in 1991.It is known that a union existed amongst London tailors as long ago as 1417 but records only date back to the 19th Century.
At the time of the merger in 1991, the NUTGW had over 70,000 members and was itself the result of many amalgamations including:
- Amalgamated Society of Journeymen Tailors
- Amalgamated Union of Clothiers' Operatives
- Amalgamated Jewish Tailors, Pressers and Machinists' Trade Union
- London Clothiers Cutters
- The Shirt, Jacket and Overall Workers
- The Belfast Shirt and Collar Workers
- Scottish National Association of Operative Tailors
- London Operative Tailors
- Amalgamated Society of Tailors and Tailoresses
In 1931 the unions formed the National Union of Tailors and Garment Workers and were joined by the United Ladies Tailors (London) and Waterproof Garment Workers' Union.
FTAT the Furniture, Timber, and Allied Trades Union merged with the GMB in 1993. FTAT can trace its origin back to 1747 and the formation of the National Society of Brushmakers and General Workers. The Union can therefore lay claim to being the oldest in the world.
At the end of the 19th century, three major unions existed in the furniture and upholstery trades: the Alliance Cabinet Makers, the United Operative Cabinet and Chairmakers' Society of Scotland and the Amalgamated Union of Upholsterers (AUU). A series of mergers culminated in the formation of the National Union of Furniture Trade Operatives (NUFTO) in 1947.
In 1971 NUFTO merged with the Amalgamated Society of Woodcutting Machinists to form FTAT.
The latest union to join the fold is the Managerial and Professional Officers a Local Government union comprising 8,000 principal officers and second tier officers. Altogether over 100 smaller unions have joined together to form the modern GMB - Britain's General Union.