It is recorded in the National Heritage List for England as a designated Grade II* listed building,[1] and is under the care of the Churches Conservation Trust.

[3] For many years St Leonard's served as the church of the port of Colchester.

[1] During the Siege of Colchester in the Civil War, Royalist soldiers took refuge in the church.

[2][4] In the earthquake of 1884 the tower was damaged and its top stage was replaced.

[2] Over the centuries the church has required repeated restoration due to subsidence, or to inadequacies in the earlier construction.