The British Rail Class 04 is a 0-6-0 diesel-mechanical shunting locomotive class, built between 1952 and 1962 and was the basis for the later Class 03 built in the British Railways workshops.

The prototype locomotive was built in 1947 and served as a departmental shunter at Hither Green depot as number DS1173, before being transferred to the capital stock list as D2341 in 1967.

The Class 04 locomotives were supplied by the Drewry Car Co., which at the time (and for most of its existence) had no manufacturing capability. Drewry sub-contracted the construction work to two builders both of whom built other locomotives under the same arrangement. Early locomotives which became D2200-41 (including DS1173) were built by Vulcan Foundry in 1952–56, and later examples D2242-2339 were built by Robert Stephenson and Hawthorns in 1956–61.

A clear line of development can be seen in the Class 04 from the 0-4-0DM locomotives built by Andrew Barclay and Drewry/Vulcan Foundry in the early 1940s. Similar 0-6-0DM locomotives had been built before the first Class 04, and others were built for industrial use.

The design continued to develop during the construction period, although this was generally confined to minor changes, including the diameter of the wheels.

The first batch (four engines numbered 11100-11103, later D2200-D2203) were equipped for street-running (see below).

The second batch (six engines numbered 11105-11110, later D2204-D2209) were fitted with conical exhaust stacks (the first batch initially had a plain exhaust "hole", later having a long, thin, and straight exhaust pipe added) and shaped cab front windows (instead of the rectangular windows of the first batch); these changes continued on all subsequent batches.

From the fourth batch (commencing with 11121, later D2215) the small cab side window of the earlier batches was replaced with a much larger window, the rear half of which slid open. The wheel diameter was also increased from 3 ft 3 in to 3 ft 6 in.