It lies within the Deanery of Westminster (St Margaret) within the Diocese of London.[1] In the period 1840–60, Pimlico was a rapidly expanding residential area and The Marquess of Westminster, the major local landowner, granted £5,000 and the freehold of a plot at the south-western end of Warwick Square for a church.[1] Immediately following all this work came a period of improvements in the chancel, funded in the main by Lord Edward Pelham-Clinton.[2] A new high altar had been installed, designed by John Francis Bentley, architect of Westminster Cathedral,[2] and now the whole chancel was lined with alabaster by Powell with Italianate mosaic designs.Particularly prominent was the new East Window by Charles Eamer Kempe depicting Christ in Glory with Saints.