The twelfth century church consisted only of the sanctuary, chancel and nave. It is easy to see that the tower was added later, the south porch later still and the west door in Victorian times.

A walk around the outside gives a fascinating glimpse of the building materials used. Kentish rag, flints and chalk from Purley, Caen stone from Normandy, pudding stone from East Ham together with some ancient Roman tiles are all easily seen on the surface of the thick rubble walls held together with Norman mortar. These is also some very good eighteen century brick-work.

The site is close to Beckton marshes, so to protect the church from rising damp, the soil all around the walls was cut away and the drainage improved. As you walk round, notice the priest's door in the south side of the apse, and the door covering the hatch from the anchorite cell in the north side of the chancel