Lainston is an abandoned village half a mile E of Sparsholt in the City of Winchester district of the county. All that remains of the village is the ruined church of St Peter which stands in the grounds of Lainston House, an H-shaped late-17thc country house, altered in the 19thc and 20thc, and now functioning as a hotel. St Peter's stands to the SW of the house, on raised ground, and is a roofless rectangular building of which the N and S walls stand to a height of 3.8 m. while the E end is completely missing. The gabled W wall survives to its full height of 6 m. There are facing doorways in the N and S walls towards the W end, a moulded fragment set in the interior wall, and inscribed ledger stones set in the floor. At the W end in the centre is an octagonal font.

Both Sparsholt and Lainston were part of the manor of Chilcomb in 1086, held by the Bishop of Winchester for the sustenance of the monks. The manor was a large one with 9 churches and 165 households in all, and it was divided among several tenants. By the reign of Henry II, lands in Sparsholt were held by Geoffrey de Caritate, and it was their holdings that eventually became the manor of Lainston, which is not known by that name before 1342.

The church is best known for the secret marriage of Elizabeth Chudleigh, Maid of Honour to Augusta, Princess of Wales and Augustus Hervey, later 3rd Earl of Bristol in 1743. When she married again, to Evelyn Pierrepont, Duke of Kingston upon Hull, the secret first marriage was initially found to be unproven, but after the Duke's death she faced a celebrated bigamy trial by her peers, in Westminster Hall, where she was found guilty, and hurriedly absconded to Europe, taking the Kingston fortune with her. In the floor of St Peter's are ledger stones commemorating Elizabeth's Chudleigh ancestors.

The building appears to be erected on an artificial mound, and its plain doorways, especially the S with its quadrant imposts, may well be rebuilt.