A very large parish church consisting of a 14thc. S doorway, a six-bay nave with N and S aisles and clerestory primarily of the 14thc./15thc.; a long four-bay chancel of c. 1300; and a short W tower begun in the late 15thc. and completed in 1547. There was a restoration by Temple Moore in 1914-15: the chancel was restored in 1926 by his son-in-law and successor, Leslie Moore (Brandwood (1997)). The E and W responds of both nave arcades are Romanesque.

Old Leake is referred to as 'Leak' in the Domesday Survey; there is no mention of a church here in 1086. However, it must have been a rather prosperous settlement as the Domesday Survey does list forty-one salt-houses, 32 freemen, 40 villagers, and 16 smallholders in Leake.

As Pevsner notes, the in situ E and W responds of the long, six-bay nave arcades demonstrate the large size of St. Mary's in the 12thc. Given the evidence provided by the Domesday Survey of a strong salt industry in Leake in the late 11thc., it seems clear that the church owes its large scale to the prosperity of the local salt trade.