The site of the church is slightly above the level of the river and is the place where the earliest people would have made their homes and had their place of worship; Domesday Book 1086 records a priest at Sunbury. The late Saxon church may have been on this site. By the mid-eighteenth century the church was demolished and in 1752 rebuilt. It is basically the same building today. It was designed by Stephen Wright, Master Mason, Royal Clerk of the Works at Hampton Court in 1746. Further alterations, mainly internal, were made during the 19th and 20th centuries, notably in the work by Samuel Teulon who detested the classical style. His High Victorian Gothic style left St. Mary's with a flamboyant, colourful effect.