St Mark's was originally a standard neo-Gothic building of 1871, but bombing during World War II destroyed everything but the spire and a porch. From 1958 to 1963, G. G. Pace redesigned the main body of the church in rubble-faced concrete. Its most striking feature are its windows. These are slits, in varying numbers and locations around the building.
The building proved a popular reinterpretation of the Gothic revival for the late twentieth century, and is now a listed building.