In Base Camp, members of T Patrol unpack the rum ration before setting off on patrol. The rum comes from the Supply Reserve Depot, hence the "SRD" on the jug. From the earliest times up until the late 1960s -early 1970s the British Military had a standard ration for rum and/or other alcoholic beverages. The usual was one ounce per day of distilled alcohol.
According to regulations the rum ration was only to be issued under the discretion of a divisional or equivalent commander. According to W. B. Kennedy Shaw, LRDG Intelligence Officer, "In the first year or so, till supplies in the Middle East ran short, the rank of a patrol commander seldom fell below the equivalent rank of a Major General!"