The rectangular chancel is all that remains of the medieval church. It now stands isolated in a field. In 1845-6, when the new parish church of St James was built in the village of Ireby, about a mile away, the nave and N aisle of the old church were taken down. Consequently, the baptismal font and a few other carved stones were removed to the new church (see: Ireby, St James’ Church). Some reconstruction and repairs on the surviving structure were undertaken in 1880. The walls of the present structure bear evidence of significant restorations and changes. Ireby is divided into High Ireby and Low Ireby. The Old Church of Ireby is within the boundaries of Low Ireby, as is the newer Church of St James.

This part of England was not covered by the Domesday survey of the 1080s. Before the Conquest and for awhile afterwards, Gospatric son of Maldred held Allerdale below Derwent (i.e. Allerdale N of the Derwent River), but about 1072 he was deprived of this and his other lands. Consequently he fled and eventually settled in Dunbar, Scotland. His son Dolfin was appointed vice-regent of the Carlisle lands along with another son Waldeve (or Waltheof). In 1092, however, King William II of England seized control of these lands. During the reign of King Henry I of England, Allerdale below Derwent re-appears as a ‘barony’ (Graham, p. 30). According to the Chronicon Cumbrie, the county of Cumbria had been granted to Ranulf Meschin, who in turn enfeoffed Waldeve as under tenant of Allerdale below Derwent. It would appear that when Ranulf became Earl of Chester, Waldeve became a tenant of the crown. Waldeve’s son and heir, Alan, gave the advowson of the church of Ireby with the service of Waldeve de Langthwaite to Carlisle Priory, probably about 1150. This was later confirmed by Kings Henry II (Nicolson and Burn, p. 129), Edward I and Edward III (Charter Rolls for 1290 and 1332). Alan, himself, seems to have died in the early part of the 1150s leaving no living heir. He was succeeded by William Fitz Duncan. By the early 1160s, both fitz Duncan and his son (William boy of Egremond) were dead. Alice, fitz Duncan's youngest daughter, received Allerdale below Derwent as part of her inheritance, and it remained with her and her husbands throughout the rest of the 12thc. and early 13thc. Cumberland, including Allerdale below Derwent, was under the control of the king of Scotland from 1136 to 1157.

In 1122 the priory of Carlisle had been founded and in 1133 Carlisle became a bishopric, with the cathedral and priory sharing the same church in Carlisle. The church of Ireby remained a possession of the priory until the Reformation, after which its patronage was held by the dean and chapter of Carlisle Cathedral. In the Taxtio Ecclesiastica of 1291-2, Ireby is listed simply: Ecclesia de Ireby. Gilbert Welton, Bishop of Carlisle, noted in 1355 that there was no vicarage at Ireby and that the church was served by a stipendiary chaplain (VCH, p. 136).

The date for the construction of the present structure is complex, particularly because of the heavy restorations. It has been suggested that in the 12thc. it was built in two phases, the western part earlier than the eastern part. The chancel arch is certainly much simpler than the arcading around the windows of the E wall. According to several writers, the latter phase is work of the second half of the 12c. The bell capitals and associated bases of this section of the former church point towards a date in the late part of the century or around 1200. It has also been suggested that the date for the earliest part of the church is mid-12thc. When Alan, son of Waldeve, gave the advowson of Ireby Church to Carlisle Priory, it is recorded that he gave the body of his son, also called Waldeve, along with a holy cross. This Waldeve, son of Alan, appears to have been alive when a charter was given to the Abbey of Holmcultram in 1150-2 (Lawrie, p. 197 no. CCXLIV). As Alan, himself, appears to have died in the first part of the 1150s, the date for the gift of the advowson to Carlisle Priory must be in or soon after 1150. The existence of a church at Ireby at this time is implied.

Alan, son and heir of Waldeve, gave High Ireby to Gospatric, son of Orme. Nicolson and Burn state that Gospatic then gave High Ireby to one of his sons, named Orme, who took the name 'de Ireby'. Members of this family seem to have played a prominent role in Low Ireby. The market charter of Low Ireby was granted in 1236/1237 to William de Ireby. John de Ireby was buried at the old church in the 13thc., and it is not unlikely that other members of the Ireby family were buried there, as well. About 1275, in a Memorandum of the descendants of Waldeve, Lord of Allerdale (Reg. of St Bees, p. 532), the gift of the advowson of Ireby Church to Carlisle Priory by Alan, son of Waldeve, is stated, but it also says that this had been given along with the service of a predecessor of Issac de Ireby (antecessorum Ysac de Yrby).

The bases of the E arcade at Ireby bear some similarity to those on the interior E windows at Bowness-on-Solway (Cumbria).

The semi-circular stone re-used on the W exterior wall is thought to be the tympanum from a doorway. The carved cross within a circle may be a later feature. It is carved centrally above the chancel arch but is not carved in the centre of the stone itself.

The small incised cross now at the back of the altar stone is impossible to date and its original context is unknown.

Like the small incised cross, it is not possible to date accurately the long stone on the E interior wall, which serves as a kind of altar. It appears that it may have been reused, but whether this was part of the original top of an altar or something else is uncertain.