The first recorded instance of trade union organisation of firefighters was when the Municipal Employees' Association recruited several London County Council firemen in early 1905, which by the end of the following year had grown to a branch of 500.

The Air Raid Precautions Act (1937) contained provisions for recruiting a volunteer force of auxiliaries to supplement existing fire brigades, which were called up on 1 September 1939.

The 95,000 called up (89,000 men, 6,000 women) formed the Auxiliary Fire Service (AFS) far outnumbered the around 6,000 full-time regulars.

In February 2024, 114 firefighters who had attended the Grenfell Tower fire in 2017 were awarded a total of £20m in a lawsuit led by the FBU against the Royal Borough of Kensington and Chelsea, Arconic, Celotex, and Saint-Gobain.

In 2020, the FBU co-signed a letter with Friends of the Earth and Greenpeace to Chancellor of the Exchequer Rishi Sunak warning that fire services in the UK were "exposed and ill-resourced to respond effectively to a climate in breakdown.

"[22] In 2023, the union released a report in which it said that the UK was "woefully underprepared" to handle the increased risk of wildfires caused by the climate crisis.