The following text is from the original listed building designation:
SOUTHBOROUGH BIRCHWOOD (OFF HARDINGE AVENUE) 1/1 Lady Catherine Stewart - Monument - II
Marble monument erected in 1812 in memory of Lady Catherine Stewart, sister of Lord Darnley, wife of Brigadier-General Stewart. He was later Marquis of Londonderry, in succession to Viscount Castlereagh, the Prime Minister, who was his half-brother. Diagonally-fluted cylindrical column with turned base mounted on a square plinth. Plain band around middle on which are carved the various rhymed inscriptions. Column surmounted by flattish urn on a square base. Enclosed by surround of heavy railings, the individual poles being square in section with forged arrow-head points. Corner uprights of larger section. Surround gated. See Colbran's 'Guide to Tunbridge Wells', 1840.
Listing NGR: TQ5719543226

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