The decision was made quite early in the period 1945-
Virtually nothing had been produced at Holton Heath over the period 1946-
Also in 1952 the manufacture of Cordite charges for rocket assisted take off of aircraft was started at RNCF using paste sheet from Caerwent. This was to augment supplies from commercial sources.
Over this period it had been decided to build a newer and bigger picrite plant at Caerwent and after it was commissioned in 1956 manufacture of both picrite and sulphuric acid at Holton Heat ceased. The following year the manufacture of propellant ceased for the final time and plans were made for the demolition and removal of plant and equipment and, most importantly, the clearing of the site of any residual explosive material.
Since 1947 a research laboratory, Admiralty Materials Laboratory, had been developing on the site and, with the closure of the factory, this laboratory occupied the buildings at the eastern end of the site, essentially all those in the “safe area”.