Didcot has a remote antiquity, one that stretches back over the past two thousand or more years. At the time of the Roman Conquest, the future parish was probably an area of part farmland, wood and marsh, but the greater emphasis was on marsh; which comprised practically half of the future Didcot. This marshland, which covered the low-lying land to the north of the modern railway, stretched from Sutton Courtenay in the west, (where it was known as Sutton Moor, a wild and desolate place, in later centuries), to Didcot, known simply as the Marsh, and further east as East Hagbourne Marsh. It continued on to Fulscott and the Moretons. And it was this marsh that decided that the first and all subsequent settlements should be sited on a well-watered wooded ridge that arose from the marsh. It's very probable that Didcot is one of the earliest settlements in this immediate area.

Today, the parish church (which sits on the highest point) and the houses and streets of the old village still straddle the southern incline of that ridge. The first settlement was Iron Age in origin, which after the Conquest became Romano-British; though it is impossible to say how large or for how long this community existed. The evidence of pottery found seems to suggest an existence to the second and third centuries. Several hundred-pottery shards have been found plus other material, a coffin, coins and a bronze brooch in a field that lies immediately east of the church.

The future for Didcot is even more growth. By 2000 the population. is visualised as being in the region of 25,000 plus. With these people and houses will come fresh commercial development the Orchard Shopping Centre- and improved services, both public and private.