Part of Former House of Detention, Below Kingsway College Clerkenwell Centre

This is part of the former House of Detention, located beneath the playground and main buildings of the former Hugh Myddelton Schools, now known as Kingsway College Clerkenwell Centre. The structure was built between 1845 and 1847 by William Moseley and was altered during the Second World War for use as an air-raid shelter. It is constructed of brick, stone, and wrought iron.

The largest accessible area is the former female corridor, which extends from the south-west to the north-east and features broad 'transepts' at its midpoint. Cells are located on either side of the passage, which is interrupted but not blocked by later transverse walls that serve as screens. The walls are made of brick, and the roofs consist of shallow brick arches, except for one area in the north transept, which was formerly the warders' hall and clerk's office and has granite columns and wrought iron beams. The floor is predominantly stone.

The cells have cambered-arched entrances, some retain metal window grilles, and there are cast iron 'eyes' in the walls, likely used for chaining prisoners. The female corridor was the southernmost section of the prison; to the north was a central hall, located roughly beneath the hall of the current college building, with male corridors extending to the west, north, and east, and a shorter administrative corridor to the south. Part of the western corridor is listed separately, and some areas beneath the present college building are in use by the college.