These brake third class coaches featured a lavatory compartment and were downgraded from their original composite configuration when second class tickets were abolished, the two second class compartments being made available for use by third class passengers.
These distinctive coaches had long service lives, the Southern Railway investing in electric trains rather than building new steam hauled stock suburban services. These SECR coach sets, along with many other pre-grouping suburban coaches will still in service into the British Railways period after 1948.