The West Lodge building(s) is to the east side of Blacksmith Lane at the west (main) entrance to the Chilworth Gunpowder Mills Middle Works site originally serving as an entry control point.

Following closer inspection in August 2016 it became apparent that the building had not been extended, but rather later connected to an independent closely adjacent building of two rooms by the insertion of a link structure.

It is argued below that the supposition that West Lodge was extended after 1920 is incorrect, and that the structures that make it up were all in use as part of the entry control function until the works closed in 1920.

This paper has been peer reviewed by Wayne Cocroft of Historic England (formerly English Heritage) and Glenys and Professor Alan Crocker, who have agreed the conclusion that all of the structures making up West Lodge were built for, and in use by the Gunpowder Mills some years before the site was closed in 1920.