According to tradition, which has now been verified, the organ was ordered by George III (1760-1820) and was intended for Windsor Castle. It was built by George Pike England but was never installed in the Castle for reasons unknown. It was bought for St Peter's Church by private subscription and erected in the South end of the gallery in 1796. In 1851 it was moved to the North transept, which involved the destruction of the medieval arch between transept and nave. In 1865 it was rebuilt by J. W. Walker and moved back to the North end of the gallery.
It was finally placed in its present position in 1886 although the present casework dates from a rebuild of 1896. The organ underwent a major reconstruction in 1958 when the detached console was fitted and the action was electrified. The rebuilding in 2001 was undertaken as a result of the subsidence that was affecting its foundations and the opportunity was taken to update the action with electronic components and add additional stops.
Taken from the St Peter's Church Guide Book written by Joyce Lodwick and Victor Lodwick (2002)