Ms Layton’s reminiscences include details of the leader’s working habits and routines, such as his habit of having breakfast in bed, and remaining there with a secretary and typewriter near his bedside until he got up, sometimes as late as 1pm.She said: “We of his personal staff were completely devoted to him, even though he was inclined to be impatient and demanding.”He was somebody who drew our loyalty and our deep respect and affection … The negative side was only on the surface. Underneath he was a very caring person.”Myra Nora Collyer, a secretary working in the war rooms, remembered the “masses and masses and masses of corridors” and the need for “sun ray lamps” once a week because they were working 12-hour shifts underground. Operation Desperate: A memo by some of the female staff in the War RoomsCredit:IWM/PA Credit:PRESS ASSOCIATION They worked long hours in a cramped and smoke-filled underground bunker, under constant fear of attack from the Luftwaffe.In need of a little light relief, a number of Winston Churchill’s secretaries working in the War Rooms concocted a tongue-in-cheek memo as the Prime Minister prepared to embark on his second visit to Washington at the height of World War Two.Entitled Operation Desperate, the note, typed on official paper marked Top Secret, demanded that a Force Commander be urgently dispatched from Britain to the US to obtain supplies of three “vital commodities” – silk stockings, chocolate and cosmetics.The mission was deemed a “complete success” as a member of staff who travelled in Churchill’s party the following month returned home with a stash of all three things, to the delight of the typists.The memo forms part of a cache of documents released by the Imperial War Museums in order to provide a glimpse of what life was like in the War Rooms.They mark the UK release of the film Darkest Hour, which recounts the early days of Churchill’s premiership, and are intended to entice visitors to the historic location. Dated May 9, 1942, the spoof memo is headed with the instruction “to be burnt before reading” and its authors are named as the Joint Planning Typing Pool.It goes on to state that in view of the government’s recent policy changes on coupon distribution, they had examined the situation and noticed “acute shortages” in certain luxury items.“The lack of these vital commodities is regarded as extremely serious and may, in consequence, become a source of extreme embarrassment,” it said. “This must be avoided at all costs.” Among other documents released today are a rare surviving example of a letter confirming a typist’s appointment, and insights from Churchill’s private secretary, Elizabeth Layton, and other secretaries working in the underground bunker. And Margaret Walker, employed as a typist and secretary, recalled: “He (Churchill) used to wear a siren suit and we used to see this shortish, fattish, tubby man bouncing along in a siren suit.”A siren suit, similar to a boiler suit, was an all-in-one garment which could be easily put on over other clothing and used by people who had to leave their homes for air raid shelters during bombing raids. The memo calls for “immediate steps” to be taken to explore the possibilities of US resources and proposes the early dispatch of a mission to the US, noting that a force commander had already been appointed “in anticipation of instructions”.The directive was signed by five fictional members of staff including “Nausea Basgwash” and “Deadly Nightshade”.Churchill travelled to the US by flying boat the following month, where he spent a week holding discussions with President Roosevelt in upstate New York, before a conference on strategy in Washington which discussed the Allied atom bomb project and landings in North Africa, codenamed Operation Torch. She said that Churchill’s working habits and unpredictability sometimes prompted humour amongst his staff, who likely formed close bonds as they coped with the pressure. A museum spokeswoman said the light-hearted memo gave an insight into the “dreary conditions” endured by Britons during the war. Other documents revealed by the Imperial War Museums (IWM) include early plans for the basement headquarters and security passes.Visitors to the Churchill War Rooms can see the various locations recreated for the forthcoming film, directed by Joe Wright and starring Gary Oldman as Churchill, such as the map room, the cabinet room, Churchill’s bedroom and the transatlantic telephone room. The switchboard operators and typists in Room 60Credit:IWM/PA The Map Room as it is seen todayCredit:IWM/PA The original plan for the Cabinet War Rooms Credit:IWM/PA Want the best of The Telegraph direct to your email and WhatsApp? Sign up to our free twice-daily Front Page newsletter and new audio briefings.