The church building largely dates from the mid fifteenth century, and it was significantly restored in 1856-7 by J Hicks, and his pupil Thomas Hardy, the novelist. There are some signs of an earlier church building dating from Norman times, and it is thought that the site may originally have been that of a Roman temple.
In the South (Hardy) chapel are two effigies of knights, which date from the 14th century, and which may have been brought to St Peter's at the time of the Dissolution of the Monasteries.
The organ was moved to the North chapel around 1900, having previously been located to the rear of its present position, but prior to 1857 was (it is thought) in the West end gallery, which was removed during the restoration work. The North chapel was known as the Williams chapel as it had previously been occupied by the memorial (1617) to Sir John Williams of Herringston, and his wife. This memorial was moved to the Eastern end, rotated, and elevated to accommodate the organ, and so it is now difficult to view.
At the West end of the North aisle is a memorial to Denzel, Lord Holles (1699). He was one of the M.P's who restrained the Speaker in the House of Commons in 1629, when motions critical of Charles I were passed, for which he was sent into exile.
The reredos depicts the Last Supper, and commemorates the 7th Earl of Shaftesbury, who is well known for his campaigning for the abolition of child labour in factories, and women working underground in mines. He also campaigned for more humane treatment of the mentally ill.
The final picture shows the chancel and the 1898 West window, "Behold I stand at the door and knock". To the left is the pulpit, and to the right the Lectern, both finely carved.