245, Old Marylebone Road

The building at 245 Old Marylebone Road, originally St Mark's School and now used as offices, was constructed around 1871-72 by architect Arthur Blomfield. It is a two and three-storey structure featuring a five-stage tower. The exterior is made of red brick with stone dressings and has a tiled roof.

The main entrance has an arched stone doorway with a plank doorset set between shafts, topped with a gabled drip mould. A moulded string course runs across at impost level, connecting to a smaller arched door on the right. Above the entrance, the first floor of the tower has four rectangular slitted lights, and to the right, there is an arcade of three lancet windows. Above this, a three-light window is set within a blind arch at the third stage. The fourth stage features blind circular recesses, likely intended for clocks, beneath corbel tables, while the narrow fifth stage has blind arcades of brickwork. The top stage is an open belfry with two tall pointed arches on each side, supported by stone imposts, and it culminates in a pyramidal spire with gabled louvres on each face.

Inside, there is a broad stone staircase. The lower room has a 15-light mullioned window at the south end, with additional high-placed mullioned windows along the west wall and a lowered ceiling. The upper floor features a similar south window, which has been compromised by the insertion of a fire escape, along with sash windows in recesses on the west side. The roof is arch-braced with collar trusses and iron tie-rods.

Historically, this building is believed to have been designed by Blomfield concurrently with St Mark's Church, which was consecrated on June 29, 1872. It served as part of the mission outreach of the new parish. The building is marked as a school on the Ordnance Survey map from 1894-96. Together with the church and the adjacent vicarage, the former school is part of a significant group of High Victorian religious buildings in the inner city, which was illustrated in The Architect on February 21, 1880.