The chancel arch, nave and aisles were rebuilt in several phases in the C13
The chancel is largely C15, as is the S aisle and the W tower
The nave and chancel roofs are red tile, the aisles and tower are roofed in lead
The W window is C14 of 3 lights
The chancel was rebuilt in the C15 and has two light N and S windows and a 5-light E window with vertical tracery in a four-centred head
INTERIOR: The interior is plastered but some medieval wall paintings have been exposed
The core of the interior, including the chancel arch and both nave arcades, is C13, but it was extensively remodelled in the later middle ages
The mid C13 chancel arch is of 2 chamfered orders on semi-octagonal responds with moulded capitals and bases
The chancel is largely C15, but the scar of an earlier, more steeply pitched roof remains above the chancel arch on the chancel W wall
The 5-bay S nave arcade is early to mid C13 and has one square and one chamfered order on alternating round and octagonal columns
The mid to late C13 N arcade is of 6 bays, and has two centred arches of two chamfered orders on alternately round and octagonal columns
In the chancel, C15 arch braced and wind braced of 3 bays
In the nave C15 wall plates and braces forming 4-centred arches, the boarding behind has been renewed
In the aisles, roofs of the C16, both low pitched, with moulded ridges and tie beams
The spandrels of the curved braces are carved with foliage, and there are bosses at the main intersections
Late C15 piscina in the chancel and another in the S aisle
Seating: In the nave some C15 benches with moulded top rails and ends, two with traceried backs, one of which is renewed
There is a C16 bench with linenfold panelling in the chancel
Stained Glass: Mostly C19 and early C20, but in NW window of N aisle part of a C16 roundel with the letter M. In the chancel the NE window of 1953 depicts St Martin
Wall Paintings: Several medieval wall paintings have been exposed and others probably remain under the plaster
There are also several other C17 marble wall tablets, and a large number of C17 and C18 floor slabs, to the Hawtreys in the chancel
Also in the chancel, a large, marble wall monument to Thomas Bright, vicar (d.1673/4) and to five of his infant grandchildren, erected by his son, the children's father, Jeremiah Bright (qv bread shelf) in or after 1696
There is a very large collection of hatchments, mostly in the tower
Ruislip was given to Bec Abbey in Normandy in the late C11, and the monks of Bec set up an administrative centre at Ruislip, although the parish church was never used as a monastic church
After the English property of all foreign monasteries was seized in the mid C15, the church was given to the Dean and Canons of St George's Windsor