The collection chiefly compiles Lady Onslow's personal letters written to her parents and sister "Jim" from her travels in Churchill's service. They provide first hand evidence of her experiences and include lively recollections of Churchill, descriptions of her work and colleagues, and descriptions of journeys, accommodation and surroundings. The letters are supplemented by a small number of photographs and other mementos.

The material held at Churchill Archives Centre mainly consists of Colville's diaries. They provide an insight into the decision-making of three Prime Ministers and the meetings held with other top officials, as well as the lives of key figures during World War II, and its aftermath.

"Before I forget", annotated draft of Hughes-Hallett's memoir on Combined Operations, 1941-5, including his memoir of the Dieppe Raid and the planning for D-Day (Operation Overlord); with a letter to him from Winston Churchill MP (Prime Minister), 19 September 1954

Colour film reel shot by Courtenay, mainly from his experiences in the Second World War, including footage of Winston Churchill in Canada and giving the "Iron Curtain" speech, 1946, and footage of American forces in the Pacific.

Letter from Philip Allen [Assistant Private Secretary to the Minister of Home Security] to Kathleen Hill [Secretary to WSC], confirming that a second Anderson Shelter had been sent to Chartwell [Kent].

Letter from Philip Allen [Assistant Private Secretary to the Minister of Home Security], to Kathleen Hill [Secretary to WSC], confirming that an Anderson Shelter big enough to accommodate 10 people had been despatched to Chartwell [Kent], at a cost of 11l 15s.

Letter from Mary Shearburn [Secretary to WSC, later Mary Thompson] to Philip Allen [Assistant Private Secretary to the Minister of Home Security], requesting an Anderson Shelter to fit 10 people to be delivered to Chartwell [Kent]. [Carbon].

Note from Mary Shearburn [Secretary to WSC, later Mary Thompson] to WSC, confirming that although construction of Anderson Shelters had ceased, there were a few available, at 10 pounds for a six seater, and 15 pounds for one accommodating up to 10 people [annotated by WSC, asking her to buy a large shelter for Chartwell, Kent].

Note from Mary Shearburn [Secretary to WSC, later Mary Thompson] to WSC, on air raid precautions at Chartwell [Kent], noting that there were adequate shelters for the staff and the cottages, that for anyone sleeping in the "big house" there was a cellar which would make a splendid shelter, leading out of the day nursery, and that if an Anderson Shelter were required for CSC when staying in the new cottage, a good place for it would be opposite the door to the muniment room.

Minute from Leslie Rowan [Private Secretary to WSC] to WSC, on the ration of sugar for the bees at Chartwell [Kent].

Letter from Kathleen Hill [Secretary to WSC] to Maryott Whyte, on an estimate from Hammond and Hussey Limited, for a long ladder for use at Chartwell [Kent] in case of incendiary bombs.

Letter from C R Bailey, District Technical Officer, Kent War Agricultural Executive Committee to WSC, with a report on Chartwell [Kent] that the ploughing of part of WSC's park for food production was not a success, recommending that the land should be cultivated in the spring, and then sown to permanent pasture, which could then be leased to a neighbouring farmer for grazing. [Copy].

Letter from Maryott Whyte to CSC, on ploughing of pasture at Chartwell [Kent] for cultivation, particularly the unfavourable reaction of A E Hill, the Head Gardener, also on arrangements for accommodation of WSC's secretaries during weekends at Chartwell.

Letter from CSC to WSC, further account of her lunch with the Prime Minister [see letter of 9 Jan 1916, CHAR 1/118A/19], also on the illness of Lady Airlie and CSC's YMCA work on a canteen for a munitions factory at Ponders End. Typescript transcript at CHAR 1/118B/30-32.

Letter from CSC to WSC, on preparations for the opening of "her" munitions canteen at Ponders End [Middlesex] by Lloyd George. Typescript transcript at CHAR 1/118B/44-45.

Letter from CSC to WSC, account of opening of "her" munitions factory at Ponders End [Middlesex], including speech by Lloyd George Typescript transcript at CHAR 1/118B/55-58.

Letter from CSC to WSC, account of dinner party for the Prime Minister (Herbert Asquith) and account of meeting with the Minister of Munitions (Christopher Addison) on canteens and hostels for munitions workers Typescript transcript at CHAR 1/118B/86-88.

Letter from CSC to WSC, on the Duke of Westminster's "dashing exploit", and on her munitions canteen work. Typescript transcript at CHAR 1/118B/105.

Letter from the Air Ministry (Adastral House, Kingsway [London]) to WSC informing him of his appointment as Honorary Air Commodore of No. 615 (County of Surrey) (Fighter) Squadron, Auxiliary Air Force and of the Air Council's pleasure at WSC's association with the Auxiliary Air Force.Signed typescript.

Report by the Supreme Commander, Allied Expeditionary Force [in Western Europe, United States Army], General Dwight Eisenhower, to the Combined Chiefs of Staff on the operations in Europe of the Allied Expeditionary Force, 8 June 1944 to 8 May 1945, dated 13 July 1945. In a presentation binding with an annotated dedication to WSC from Eisenhower and a note [by WSC's secretary] indicating that the gift was acknowledged on 23 January 1950.

Letter from WSC to Lieutenant-Colonel Steer-Webster thanking him for the excellent coloured reproduction of "Mulberry B" [codename for type of artificial harbour used on D-Day], asking him to thank Corporal Jobson who was responsible for the painting, and thanking him and his staff for the various models and the relief map of the Mulberry which they have sent to WSC's Map Room [carbon].

Telegram from WSC to General Dwight Eisenhower [Supreme Commander Allied Expeditionary Force in Western Europe, United States Army] marked "personal and Top Secret" congratulating him on the great victory won by the armies under his command [achieving a bridgehead over the Rhine at Remagan, Germany]. Photocopy.

Telegram from General Sir Archibald Wavell [Supreme Commander, South West Pacific] to WSC regarding military command in Burma [later Myanmar]: feels disturbed at the "lack of real fighting spirit" shown by troops in Malaya [later Malaysia] and Burma, and lists some causes; comments on Lieutenant-General Thomas Hutton [General Officer Commanding, Burma] and proposal to replace him with General Harold Alexander; refers to own rapid recovery.