Black Friday (1921)

Black Friday, in British labour history, refers to 15 April 1921, when the leaders of transport and rail unions announced a decision not to call for strike action in support of the miners. The epithet 'black' derives from a widespread feeling amongst labour radicals that the decision amounted to a breach of solidarity and a betrayal of the miners.

Black Friday caused the 1921 United Kingdom census, which had been planned for 24 April, to be pushed back to June.