On 18th January 1943, Lieutenant J.R. Bainbridge photographed a B.T.N.I. Security Poster marked "Most Secret" at a location somewhere in Northern Ireland.
Between March 1941 and March 1942, 5th Infantry Division as a whole operated in Ulster under British Troops in Northern Ireland (B.T.N.I.) providing defence.
After the fall of France in June 1940, 61st Infantry Division, British Army deployed to Northern Ireland under the command of Major-General Carton de Wiart.
53rd (Welsh) Infantry Division arrived in Northern Ireland in 1940 following the fall of France. The aim was to protect Ulster from the threat of Nazi invasion.
59th (Staffordshire) Infantry Division arrived in Northern Ireland in November 1941, falling under British Troops Northern Ireland from June the following year.
On 16th February 1943, 72nd Independent Infantry Brigade trained in Co. Down using a raft of iron and waterproofing to cross Corbet Lough carrying vehicles.
148th Independent Infantry Brigade derved under British Troops in Northern Ireland from 7th July 1940 - 26th April 1942 to counter a potential German invasion.
In 1940, during the Second World War, with the threat of Operation SEA LION in the air, 9th Battalion, Gloucestershire Regiment were sent to Northern Ireland.