Decline had already set in: the church was disused by 1596, and the parish only had one other inhabited dwelling. The Church Commissioners declared the structure ruined in the 17th century, and only the four walls were left by the early 19th century. For many years during that century, the structure was used as a henhouse by nearby farmers. The Scrase family and their descendants had lived in West Blatchington manor for more than four centuries, and were held responsible by some for the failure to restore the church earlier than it eventually was. Vicar of Brighton Rev. Henry Michell Wagner proposed a new church, school and graveyard in the village in 1855; these would have been built at his own expense. Two acres of farmland were needed; these were owned by the main local landowner the Marquess of Abergavenny but farmed by his tenants, the Hobson family (descendants of the Scrases). The Marquess agreed but his tenants refused to give the land up, so the plan was put on hold. However, when one of the Hobsons died in 1888, she left money in her will to restore the old church. Somers Clarke, a Brighton native who was responsible for several church restorations and alterations in the area in the late 19th century, was chosen for the work. St Peter's was reopened for worship on 29 June 1891. Hove expanded significantly in the first half of the 20th century, and the ancient village of West Blatchington was entirely surrounded by suburban residential development, encouraged by its inclusion in the newly created Borough of Hove in 1928. The rebuilt church was too small for the local population, and more changes were planned. On 8 May 1960 the foundation stone of a large extension on the north side was laid by the Bishop of Chichester, Roger Plumpton Wilson. As at St Leonard's Church, Aldrington, another church in Hove, the extension was essentially a new church built around the existing structure. John Leopold Denman was employed as the architect; he built the exterior in flint and retained the old north wall, which helped the extension to fit in well with the 11th- and 19th-century parts of the church. An unusual arrangement at roof level brings natural light into, and physically links, the old and new parts of the church: there is a group of dormer window-style skylights arranged like a clerestory. The work was completed by 1962. The entrance porch was restored in 1987.