Clapton Mill (Lockyer and Son), with aqueduct to north east

Clapton Mill (Lockyer and Son), with its associated aqueduct, is a water-driven flour mill rebuilt in 1864 on the site of a medieval mill dating back to around the 12th century. The building is constructed of local stone with Ham stone ashlar dressings, and is roofed with Welsh slate, featuring plain bargeboarded gables.

The main three-storey block has an attic and comprises four bays. It features chamfer-mullioned windows, all three-light, with cast iron casements and rectangular panes. Metal plate reinforcements are visible at the ends of the beams. A boarded door is set within a moulded flat-arched surround to the lower bay, while plain doorways provide access to the first and second floors in the second bay. Above the doorways is a projecting timber-framed structure clad in corrugated iron, used as a sack hoist, supported by timber brackets on stone corbels and topped with a pitched, gabled roof. A simple window and trap doors are also incorporated into the hoist.

Adjacent to the south gable is a single-storey building with segmental-arched openings to two casement windows and a brick south gable. This is the diesel engine house, dating probably from 1931, housing a Ruston and Hornsby engine which supplements the water wheel drive when necessary. Behind the engine house are apertures revealing the wheelhouse, containing a small segmental-arched opening and a larger three-centred arch which overlooks the millstream that runs along the rear of the building. A two-light window is set high in the main south gable, with two further windows below. Two lean-to buildings are attached to the north gable, a smaller one against a larger.

The rear, east elevation is in brick. Attached to the north-east corner is a steel plate conduit aqueduct, supported by brick piers over a length of 20-30 metres. The undershot and breastshot water wheel is made of cast iron, measuring 6.4 metres in diameter and approximately 3 metres across. It was originally made in Dorset and later repaired by a Martock firm. The associated machinery, largely installed in 1864 and with appropriate renewals, remains, and includes Derbyshire and French millstones. The interior framework is primarily timber, with cast iron columns. Original ladder stairs lead to an attic containing ten bin stores.

The Lockyer family took over as tenant millers in 1870 and purchased the mill in 1901. It continues to be operated by a Lockyer father and son (as of 1986) and has largely avoided alterations that would be necessary to meet modern health and safety regulations, as such changes would likely compromise its historical interest and significance. The mill is designated at Grade II* for the survival of its original machinery.