In the early 1990s, the Class 307 passenger units were being withdrawn from service. At the same time, the Parcels sector of British Rail were looking for a fleet of parcels multiple units, which would be more cost effective to run than locomotive-hauled stock as previously used. One suggestion was to convert a number of Class 307 units to meet the need, as had been done with four of the similar Class 302 units, and several Class 307 units were set aside and stored with this possibility in mind.
However, the age and design of the units counted against them, and the decision was taken instead to build new units, which became the Class 325. However, the driving cars from the Class 307s were still used by the Parcels sector. They were converted into Propelling Control Vehicles (PCV) and used as a kind of driving trailer car at the end of locomotive-hauled parcels trains.