Their parapets copy the tower, and they have C15-style windows.
By the late C18, the old chapel had become too small for the growing population of the town, and it was rebuilt in a contemporary style but retained the medieval tower, following a collection made in 1784-5.
It was stripped of many liturgical furnishings in the 1970s, when the pulpit and choir stalls were removed and the altar moved forward.
SOURCES Buildings of England: Essex , 135 RCHME Essex IV REASONS FOR DESIGNATION: The church of St Mary Magdalene, Billericay, Essex is designated at Grade II* for the following principal reasons: * Excellent C15 brick tower with C19 side extensions on a good brick preaching-box church of the later C18. * Internally it has galleries of 1845 to N, S and W. * The combination of late medieval tower with tall Georgian body, a fusion of Gothic and Classical form, is usual and possesses high townscape value.