His Majesty's Factory, Gretna, or HM Factory, Gretna as it was usually known, was a UK government World War I Cordite factory, adjacent to the Solway Firth, near Gretna in Dumfries-shire (now Dumfries and Galloway). It was built by the Ministry of Munitions in direct response to the Shell Crisis of 1915, when an acute shortage of explosives was seriously hampering the war effort.

The complex straddled the Scottish/English border; stretching some 12 miles from Mossband near Longtown, in the east, to Dornock/Eastriggs in the west.

Construction work started in November 1915. As part of the construction work it was necessary to build two wooden townships to house the workers, including much of the township of Gretna and the village of Eastriggs. The influx of navvies and munitions workers was met with the introduction of liquor control, including the nationalisation of pubs and brewing in the vicinity. Production of munitions started in April 1916, when a large proportion of its workers were women: in 1917, for example, there were 11,576 women and 5,066 men on the site.

In 1917, when production reached 800 tons per week, King George V and Queen Mary made an official visit to the factory.

The factory was known locally as "The Devil's Porridge Factory" because of the way the explosives were mixed in the production process, and the people of the region still refer to the disused site in the same way. It was a most unpleasant and unhealthy place to work, and the fact that thousands of men and women, although housed separately, were in close proximity to each other with little to occupy their off-duty hours was of great to concern to the authorities – and of even greater concern to local church officials.

The Gretna factory and other munitions plants throughout the UK were policed mainly by women officers. There were no fewer than seventy-six women police employed at Gretna during the War. We'd like to thank John Green for sending us the photographs below of cap badges and the two women officers.