The church is on a site of religious significance, at the highest point on a ridge. A 1200 year old yew tree is close to that point. This was the heart of a Saxon settlement, perhaps with a wooden church. There has always been a story that Berin, the great British missionary, preached to the people here. He later became Bishop of Dorchester, and history calls him St. Birinus.
The foundations of our church were laid in 1160. The church developed in four distinct areas. The earliest is the twelfth century nave. In the fourteenth century the chancel and the south aisle were added. Five hundred years later, the north aisle, kitchen and vestry were built. The belfy is from the nineteenth century, a solid timber frame covered with oak shingles and surmounted by a broad spire of the same materials. There are three bells, two are from the late fourteenth century and bear the stamp of the Wallingford foundry and the third was cast in Reading.
The font is of Norman workmanship. it is large and low, tub-shaped with a plain bowl. It stands by the western column of the south nave. One of the more interesting onjects is nearby - a carved recumbant figure of an abbot in full vestments, wearing a mitre. Conjecture has him either as Ralph de Dudcote, Abbot of Dorchester or as Richard de Hendred, Abbot of Abingdon. Several pieces of stained glass survive from the Middle Ages, in the top of the West Window. The parish chest, probably about six hundred years old, is a 'dug out' chest. Its sides are inches thick and it has a massive lid with three huge clasps. In former times it would have held the parish records and plate. A wooden rood screen with carved figures of the crucifixion was put in place as a war memorial after the First World War, containing the names of those killed in the Great War. Many years later the rood screen was removed and parts of it used to create a vestry for the Rector. More recently the crucifix (from the top of the screen) was hung from the chancel arch, where it is now.
The clergy and lords of Didcot Manor connect All Saints to significant events in English history, the Civil War between Stephen and Matilda, King John's suppression of the Jews, the Montford Rebellion and the Gunpowder Plot.