Alterations to Piccadilly Building including erection of 3-storey extension to east and south and addition of new mansard roof at third floor to provide additional church office and meeting room accommodation; new plant rooms at basement level, plant at new third floor level, new service tower within Piccadilly Building and demolition of vestry link building to create new entry to Church yard from Church Place; relocation of rectory accommodation from Piccadilly Building into Jermyn Street Building and erection of new second floor mansard to Jermyn Street Building to support rectory use; relocation of existing cafe accommodation from ground floor of Jermyn Street Building into ground and part basement floor of Piccadilly Building; alterations to St James's church including repair of spire, installation of plant within former bell tower, excavation beneath the south porch of the church; and reinstatement of south entrance door; alteration of Jermyn Street Building to provide new route between Jermyn Street and the churchyard, new railings to Jermyn Street, and re-landscaping of the North and Green Churchyards, and erection of new single storey garden pavilion in Green Churchyard.

Creation of residential unit (Class C3) at basement level and insertion of front lightwell grill, continued use of ground floor as an office (Class E), alterations to windows and doors in rear lightwell, the erection of a roof extension on building at rear associated with continued of building for residential purposes as well as landscaping works in rear garden.