Description from record TQ 85 SW 33 :
Ruins of Barbicans and Dam at Leeds Castle, Grade I. Triple barbican. Ruins of 2 of the island barbicans with incorporated mill survive, with dam to south-east. Irregular height. Outer barbican: rectangular, aligned north-south, with curved south-west corner. Connected to dam by stone wall with small arch. Causeway to north. Pointed arched stone bridge with parapet, formerly a drawbridge, linking to inner barbican. Inner barbican: roughly rectangular, parallel to east of outer barbican, with deep room, possibly a guard room, immediately to south of bridge. Linked to larger island of castle to east by stone bridge, formerly a drawbridge, and to broad causeways to south-east and south-west. South end of west wall turns south-west to form one wall of south-west causeway or dam. (1) Additional bibliography. (2)(3)

The following text is from the original listed building designation:
BROOMFIELD Ruins of Barbicans TQ 85 SW and Dam at Leeds 2/1 Castle GV I
Partly in Leeds civil parish. Triple barbican. Ruins of 2 of the island barbicans with incorporated mill survive, with dam to south-east. Probably early-to-mid C13. Mill repaired 1298-9. Stone. Irregular height. Outer barbican: rectangular, aligned north-south, with curved south-west corner, and incorporating ruins of former mill within north-west corner. Connected to dam by stone wall with small arch. Causeway to north. Pointed arched stone bridge with parapet, formerly a drawbridge, linking to inner barbican. Inner barbican: roughly rectangular, parallel to east of outer barbican, with deep room, possibly a guard room, immediately to south of bridge. Linked to larger island of castle to east by stone bridge, formerly a drawbridge, and to broad causeways to south-east and south-west. South end of west wall turns south-west to form one wall of south-west causeway or dam. Various window openings and loop lights. North gateway to outer barbican with depressed-pointed arch and portcullis groove. Inner barbican has similar gateway to bridge between barbicans, and one jamb of gateway to former south-west bridge and causeway. See also Leeds Castle [Item 2/2].
Listing NGR: TQ8184352984 (4)

<1> DOE (HHR) Borough of Maidstone Kent 18 December 1985 3 (OS Card Reference). SKE39921.

<2> Bldgs of Eng-West Kent & the Weald 1980 371 (J Newman) (OS Card Reference). SKE38149.

<3> Arch Cant 95 1979 296 (D Nash) (OS Card Reference). SKE36225.

<4> English Heritage, List of Buildings of Special Architectural or Historic Interest (Map). SKE16160.