Thunderfield Castle medieval moated site


Heritage Category:
Scheduled Monument
List Entry Number:
Date first listed:
Date of most recent amendment:


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The building or site itself may lie within the boundary of more than one authority.

Reigate and Banstead (District Authority)
National Grid Reference:
TQ 29996 42582

Reasons for Designation

Around 6,000 moated sites are known in England. They consist of wide ditches, often or seasonally water-filled, partly or completely enclosing one or more islands of dry ground on which stood domestic or religious buildings. In some cases the islands were used for horticulture. The majority of moated sites served as prestigious aristocratic and seigneurial residences with the provision of a moat intended as a status symbol rather than a practical military defence. The peak period during which moated sites were built was between about 1250 and 1350 and by far the greatest concentration lies in central and eastern parts of England. However, moated sites were built throughout the medieval period, are widely scattered throughout England and exhibit a high level of diversity in their forms and sizes. They form a significant class of medieval monument and are important for the understanding of the distribution of wealth and status in the countryside. Many examples provide conditions favourable to the survival of organic remains.

Thunderfield, with its diversity of component parts including a double circuit of moats, is one of a very small number of complex moated sites in the South East. The large expanses of undeveloped land within the moats makes the monument of high archaeological potential, especially in the light of the small scale excavations which have demonstrated that archaeological remains do survive in the interior. In addition, historical research has revealed a considerable quantity of information on the former importance of the manor centred here.


Thunderfield Castle, a name applied to the monument only since the 17th century, is the site of a medieval moated manor house. The original manor name of Herewoldsle or Harrowsley is preserved in many of the local placenames. The monument includes a central rectangular moat island 55m by 40m, a moat 7-8m across with a semi-circular extension on the northern side, an intermediate bank of earth up to 1.2m high and 8m wide, and an outer moat averaging 6m across. Small-scale excavation in 1936 confirmed the occupation of the site during the 13th-15th centuries. At Thunderfield, the central island is likely to have provided the site for the main house, while ancillary structures such as stables, storehouses etc are likely to have stood nearby. The semi-circular extension to the inner moat is best seen as marking the site of a gatehouse and original approach to the island. The outer moat appears to have been stream-fed from the south, unlike the inner moat which was spring-fed. An overflow channel, now infilled, carried water from the inner moat at its north-west corner. The modern buildings and bridges within the constraint area are excluded from the scheduling, although the ground beneath each remains included. Also excluded is the surface of the access road and the service trench beneath it.

MAP EXTRACT The site of the monument is shown on the attached map extract.


The contents of this record have been generated from a legacy data system.

Legacy System number:
Legacy System:


Books and journals
Braun, H, 'Surrey Arch. Coll' in Surrey Arch. Coll, , Vol. 45, (1937)
Title: Ordnance Survey County Series Surrey XLII (NW) Source Date: Author: Publisher: Surveyor:
Turner, D., Unpublished M.S., Typescript on file


This monument is scheduled under the Ancient Monuments and Archaeological Areas Act 1979 as amended as it appears to the Secretary of State to be of national importance. This entry is a copy, the original is held by the Department for Digital, Culture, Media and Sport.

End of official listing

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