Tucked away beneath a modern office block is one of Reigate’s best kept secrets. This hidden undercroft is a rare architectural survivor of the town’s medieval past.
In medieval architecture, an undercroft was a strong, vaulted chamber typically constructed beneath a primary building. The word ‘croft’ came from the Latin word crypta, meaning a crypt, vault, or hidden cavern. Though sometimes referred to as cellars, undercrofts were not always built entirely underground; instead, they often sat at ground or semi-sunken levels to support the main living or commercial spaces above.
Medieval towns were highly vulnerable to fire so merchants invested heavily in stone masonry to build these secure, fireproof rooms. Placed directly below a house or market, an undercroft allowed owners close supervision of valuable provisions, expensive fabrics, or wine and oil.
While the timber-framed structures above them have mostly been destroyed by fire, rot, or redevelopment, the heavy stone vaults of undercrofts have frequently survived, leaving a subterranean map of medieval wealth across Europe.
The Reigate medieval undercroft is prime example of this architectural survival. Situated between West Street and Slipshoe Street, the entrance is in the south-west corner.
Dating back to the late 14th or 15th century, this structure measures 5 metres by 3.5 metres and features a depressed three-centred tunnel vault reinforced by five chamfered ribs, one of which is missing. It has walls of roughly-coursed rubble up to 2.7m high and a cobbled floor, with two wall niches.
It is likely that the undercroft originally extended further northwards. It would have been lit by two unglazed square windows, one in the east wall and another in the south wall.
Local historians think the town’s original marketplace was in this part of Reigate before it was moved east down the High Street. The undercroft is believed to have served as the basement of a medieval market house or court house, with its rugged stone walls and secure layout potentially doubling as a local lock-up.
When the civic building above it fell into ruin and was demolished around 1728, the undercroft was packed with rubbish and forgotten for nearly two centuries. Following rediscovery, the chamber was cleared and restored.
Now sitting beneath a modern office building, it was registered as a Scheduled Monument with Historic England in 1962. The one window (pictured) has now been opened to provide light and ventilation.
The Reigate undercroft is generally closed to the general public because it sits under private commercial premises. There are occasional, pre-arranged civic tours during the annual Heritage Open Days scheme in September.
https://historicengland.org.uk
Photograph of the Medieval Undercroft, (2011) Ian Capper