Aerial searchlights must immediately be got ready for use in conjunction with the aerial guns. Propose me without delay the quickest means of meeting this need, with estimates of time and money. At least thirty or forty aerial searchlights are required. ‘Vernon’[62] should co-operate. Drastic and energetic action is required. 2. Let me have a return on one sheet of paper showing all anti-aircraft guns, regular or improvised, available afloat and ashore, at the present time; and what deliveries may be expected in the next two months. Let me have also any suggestions for increasing their number. No one can doubt that aerial attack upon England must be a feature of the near future. _September 5, 1914._ Secretary. First Sea Lord. Third Sea Lord. Chief of Staff. Director of Naval Ordnance. Director of Air Division. There can be no question of defending London by artillery against aerial attack. It is quite impossible to cover so vast an area; and if London, why not every other city? Defence against aircraft by guns is limited absolutely to points of military value.... Far more important than London are the vulnerable points in the Medway and at Dover and Portsmouth. Oil-tanks, power-houses, lock-gates, magazines, airship sheds, all require to have their aerial guns increased in number. Portsmouth in particular requires attention now that enemy’s territory has come so near. Aerial searchlights must be provided in connection with every group of guns.... But, after all, the great defence against aerial menace is to attack the enemy’s aircraft as near as possible to their point of departure. Director of Air Division has already received directions on this. The principle is as follows:— (_a_) A strong oversea force of aeroplanes to deny the French and Belgian coasts to the enemy’s aircraft, and to attack all Zeppelins and air bases or temporary air bases which it may be sought to establish, and which are in reach. (_b_) We must be in constant telegraphic and telephonic communication with the oversea aeroplane squadrons. We must maintain an intercepting force of aeroplanes and airships at some convenient point within range of a line drawn from Dover to London, and local defence flights at Eastchurch and Calshot. (_c_) A squadron of aeroplanes will be established at Hendon, also in telephonic communication with the other stations, for the purpose of attacking enemy aircraft which may attempt to molest London. Landing grounds must be prepared in all the parks; railings must be removed, and the area marked out by a large white circle by day and by a good system of lighting at night. It is indispensable that airmen of the Hendon flight should be able to fly by night, and their machines must be fitted with the necessary lights and instruments.