The medieval church was accidentally burnt down on 24th June 1782. The remaining tower is 14th century, and of local rubble flint.
The tower was consciously retained after the fire to provide a romantic focal point in the landscape park laid out in Fornham Park in the late 18th century. Capability Brown, who died in 1783, visited Fornham in 1781 and again in 1782 after the fire. He produced schemes for the park and for rebuilding the church, but the extent of his contribution is not certain at present.
The tower is interesting from an ecclesiological point of view, because it never underwent Victorian restoration. It is probably what many East Anglian towers looked like before their bell windows were renewed.