This batch of 32 four-car sets, built at Eastleigh on frames from Ashford were introduced for the Liverpool Street-Southend route and were originally fitted for 1,500v dc overhead operation. The sets had the power collection pantograph above the guards van on the MBS. Passenger accommodation was in a mix of 3+2 and compartments. The livery applied was multiple unit green. Front end indication was provided by white lights with a destination indicator at the top centre of the front end.
In 1960s when the dc overhead system was replaced by 25kV ac overhead, the sets were rebuilt at Eastleigh works, to accommodate the new equipment, the guards brake van and pantograph were moved to the former DTS vehicle which now became a DTBS. The former guards van area in the motor car was replaced by a seating area.
The sets remained on the Southend and other Great Eastern routes and the next major change was full refurbishment in 1983-84 at Eastleigh, when all compartment vehicles were opened out and the first class area in the TC vehicles turned over to standard class use, while a new 24 seat first class area was provided in the former DTS which became a DTC coach.
From 1967 the sets started to appear in all over rail blue, after refurbishment this gave way to blue and grey. After the formation of NSE the sets emerged in Network South East colours.
A number of Class 307s were transferred to West Yorkshire at Leeds Neville Hill depot in 1990 for local electrified area operation, these were replaced after a short time by spare Class 308s
The Class 307 fleet were withdrawn in 1993, with the majority of DTC vehicles being converted to propelling Control vehicles (PCVs) for the EWS/Rail express Systems function.