SD:Cromwell IV OP (140mm)

 is a British Artillery unit.

Overview
The Cromwell IV OP is a Cromwell IVconverted to an observation post, directing off-map BL 5.5-inch Medium Gun Artillery to a given location. BL 5.5-inch Medium Gun were organized into Medium Regiments each with 8 guns. These Medium Regiments were organized into Army Group Royal Artillery.