The BR Standard Class 3 2-6-2T was a class of steam locomotive designed by Robert Riddles for British Railways. It was essentially a hybrid design, the chassis being closely based on and sharing a number of parts with the LMS Ivatt Class 4, and having a boiler derived from a GWR No.2 boiler as fitted to the GWR Large Prairie 2-6-2T and 5600 Class 0-6-2T tank engines.

From new, they were based on the Western Region, Southern Region, North Eastern Region and London Midland Region. The class had a short life as most of the work that they had been built for soon disappeared with the branch lines and the introduction of DMU services on shorter routes. 

When delivered new the class all carried BR lined MT black livery. From 1957 onwards, those members of the class based on the Western Region started to receive lined green livery. From the early 1960s, some Western Region class members also received unlined green livery as an economy measure. Those class members allocated to other regions retained lined black livery until withdrawal.