The prototype (of 1947) was numbered DS1173 in departmental service.
The first 60 production units (from 1952) were numbered in the sequences 11100–11103, 11105–11115, 11121–11135, 11149–11160, and 11212–11229.

From 1957, new production units received numbers in the D-prefix ("Pre-TOPS") numbering series.
All existing units were renumbered in the same series, sequentially from D2200 to D2259, with the new production units continuing from D2260 to D2340.
Finally, the prototype locomotive left departmental service and entered the service fleet, being re-numbered as D2341; thus the oldest example of the class was allocated the last number in the numbering sequence.
The prototype (of 1947) was numbered DS1173 in departmental service. The first 60 production units (from 1952) were numbered in the sequences 11100–11103, 11105–11115, 11121–11135, 11149–11160, and 11212–11229.
From 1957, new production units received numbers in the D-prefix ("Pre-TOPS") numbering series. All existing units were renumbered in the same series, sequentially from D2200 to D2259, with the new production units continuing from D2260 to D2340. Finally, the prototype locomotive left departmental service and entered the service fleet, being re-numbered as D2341; thus the oldest example of the class was allocated the last number in the numbering sequence.
British Rail Class 04