The steam locomotives of British Railways were used by British Railways over the period 1948–1968. The vast majority of these were inherited from its four constituent companies, the "Big Four".
In addition, BR built 2,537 steam locomotives in the period 1948–1960, 1,538 to pre-nationalisation designs and 999 to its own standard designs. These locomotives had short working lives, some as little as five years, because of the decision to end the use of steam traction by 1968, against a design life of over 30 years and a theoretical final withdrawal date of between 1990 and 2000.