Correspondence between Sir Thomas Inskip [later 1st Lord Caldecote], Minister for Co-ordination of Defence and WSC on subjects including: the Fleet Air Arm; progress in the 1922 Committee on realizing the inadequacy of air defences and general delays in the committee; the possibility of an airborne invasion; the usefulness of WSC's advice; the role of a Minister of Supply; the visit and report of Allen Clark, Joint Managing Director of Plessey Company Limited, to German munitions works; French estimates of German air power; the difficulty of Inskip's work, and the need for a powerful mechanism for supply to the Services, and an organization of war industry, before war breaks out; asking WSC to join the Committee of Imperial Defence sub-committee on Air Defence Research; building capital ships to withstand mines, torpedoes and bombs; Inskip's commitment to do nothing that would disturb normal trade; the use of the Territorial Army in defence against airborne attack; trials of a new machine pistol; the unreliability of Government information, particularly on German and British air strength, and WSC's own information.Also includes: memorandum on WSC's expected contribution to the Air Defence Research sub-committee; copy of a letter from Violet Pearman [Secretary to WSC] to Sir Austen Chamberlain; press cutting on a statement by Inskip on the complacency of Government critics putting their own sources of information above those of the Government, and on the Government's extended air defence scheme.