Of the three 2-6-0 BR Standard locomotives, the biggest was the class 4. It was developed by Robert Riddles at Doncaster and based on the LMS Ivatt class 4. Although classified as mixed traffic locomotives, they were primarily intended for use in freight service. But although they had a driver diameter of only 5 ft 3 in, they were nevertheless regularly used in passenger service.

They used the same cylinders as the class 3 tender and tank locomotives, but had a larger boiler and a higher pressure. Like all BR standard locomotives, they had outside cylinders and outside Valve gear. With an axle load as low as 16 tons 15 cwt, they could be operated almost everywhere.

The first 70 were built at Doncaster and 45 more at Horwich. At both of these works, the last class 4 was also the last steam locomotive built there. They were allocated to all BR regions except the Western Region. With a total of 37 and 35, the Scottish and Southern Regions got the most. They were withdrawn between 1964 and 1967 and four are preserved. Three of these have been operational again, with only 76017 being operational today. 76077 is now being restored to be operational again.