215 Lord Cranborne, U.K. Secretary of State for Dominion Affairs, to Mr John Curtin, Prime Minister
Circular cablegram M476 LONDON, 23 December 1941, 3.40 a.m.
IMMEDIATE MOST SECRET
The following message which is of the highest degree of secrecy is for the Prime Minister.
The Defence Committee of War Cabinet have now completed their preliminary examination of the situation presented by the opening phase of the Japanese attack on ourselves and on the United States. Their appreciation of the situation and the immediate steps that have been ordered are summarised in the following paragraphs.  A copy of the full report has been sent to the Prime Minister  at Washington. Summary begins.
(A) Future British naval strategy (1) We must ensure sea communications in the Atlantic first, those in the Indian Ocean second. Limited United States Naval support can be expected in the Atlantic where our mutual interests coincide and from the United States Asiatic Fleet-but not elsewhere.
(Note: Calculations are based on the assumption that 'SCHARNHORST' and 'GNEISENAU' at Brest are kept out of action. Unless concrete evidence is forthcoming of the damage inflicted on those ships it may be necessary to retain additional heavy ships in the North Atlantic area thereby simultaneously with the formation of an Eastern Fleet.) (2) Simultaneous withdrawal of capital ships from both the Eastern and Western Mediterranean is unsound.
(3) There is not one base which would be acceptable to both the United States and ourselves as affording sufficient protection to the interests of each at which our own and United States Forces equal or superior to the Japanese can be assembled.
(4) Apart from the question of fighter protection we ourselves can not provide a balanced fleet at Singapore at once. Therefore unsound to send capital ships there at present.
(5) To produce the required fleet ourselves it will be necessary to withdraw capital ships from the Eastern Mediterranean. This withdrawal can only be offset by maintaining sufficient air striking forces at Malta and in Cyrenaica to make, in conjunction with our submarines, operation of Italian heavy ships against our supply routes too hazardous.
(6) Pending assembly of a fleet in the Indian Ocean we must expect Japanese raiding forces in that Sea. But until the Japanese secure Borneo or an area to the South for the establishment of shore bases for aircraft within range of Sunda Straits routes, escorted convoys should be able to reach Singapore.
(7) When a fleet has been assembled in the Indian Ocean its action will depend on the conditions prevailing. It may have to relieve Singapore or repel a threat to Australia and New Zealand or operate for a time from its Indian Ocean base.
(B) Wider implications of the war in the Far East (8) In the Far East our object must be to retain such points as will prevent the Japanese from using our vital interests in that area and as will enable us later to attack and defeat Japan. In both phases United States co-operation and assistance will be essential. It will not be sufficient for them to maintain a defensive attitude. We shall in addition require Chinese help for the final defeat of Japan. Cooperation with Chiang Kai-shek  must therefore remain a cardinal point in allied policy.
(9) To achieve our object we must hold:
(a) in the Indian Ocean.
(i) Burma (particularly Rangoon and the Irrawaddy Basin).
(ii) Ceylon and other naval and air bases.
We recognise the importance of providing adequately for land and air defence of Burma both for immediately defensive and eventually offensive needs. Burma also contains our only effective lines of communication with China whose continued resistance is of such great value. (Ceylon for naval reasons is equally important.) (b) in the East Indies Area.
(i) Singapore Island and Southern Malaya to give depth to defence.
(ii) Java and Southern Sumatra.
(10) United States authorities in a recent re-appreciation have stated that their strategic requirements necessitated their holding Wake Island, Hawaii, Samoa, Midway Island, Johnston Island and Palmyra. In order to be able to assist us in offensive action against Japan the United States are being urged to make every effort to hold Manila.
(11) Our position in Malaya is very serious. We have no balanced fleet in the Far Eastern waters; our air and land forces are heavily outnumbered. It is of the greatest importance to hold Singapore. The Japanese advance in Malaya must be disputed inch by inch. The Commander-in-Chief of the Far East  has been told that nothing compares in importance with Singapore which is to be held at all costs. But should we in spite of our efforts be forced out of Malaya we must make every effort to hold the other essential points in the East Indies, retention of which provide a barrier to the Indian Ocean and Australia.
(12) The main considerations in connection with a return to the offensive are:
(a) Assembly in the Indian Ocean of a Fleet of nine capital ships and four aircraft carriers. This will necessarily mean increased commitments for our land and air forces in the Middle East.
(b) The Far and Middle Easts are inter-dependent. We cannot afford entirely to relax our grip on either unless in the last resort the security of the United Kingdom or the Dominions demands it.
Provided that our offensive in Libya is completely successful and Benghazi remains in our hands, some risk in the Eastern Mediterranean will be justified particularly in view of Russia's successes which have postponed, for some months at least, the threat to the Caucasus and thence to our Northern flank.
(C) The main conclusions (and note of action already taken) (13) Unified direction and closest co-ordination of all allied forces should be secured as soon as possible. Offensive action against Japan should be concerted forthwith between the United States and our staffs.
These questions are being urgently pursued.
(14) It is very necessary that United States Forces should act offensively on sea, land and in the air and at once. From the point of view of the allies the retention of the Philippine Islands is of first importance. We are asking that this should be urgently pressed.
(15) We should assemble a capital ship fleet in the Indian Ocean as soon as possible. In the meantime we must rely mainly on aircraft carriers.
(16) We must contrive to fight the best possible delaying action in Malaya, the Southern part of which is vital to the security of Singapore Island.
(17) We must maintain Sunda Straits route to Singapore. The Commander-in-Chief, Far East, has been instructed to co-ordinate with the Dutch best possible arrangements for the maintenance of this route.
(18) Immediate steps should be taken to provide adequate defences and facilities in Burma and at ports and bases which will be required in the Indian Ocean and South Pacific, for operation of Naval, Military and Air Forces and reception of supplies and reinforcements.
(19) Land Forces. Reinforcements must be rushed to Malaya and Burma as soon as possible. The extent to which we can reinforce Malaya will depend largely on our ability to convey forces to Singapore and to maintain them there.
(20) The 18th Division, which was on its way to the Middle East and has now passed the Cape, together with the 17th (Indian) Division which was destined for Iraq have been placed at the disposal of the Commander-in-Chief, India, for reinforcement of Burma and Malaya. It has been decided that the leading brigade group of the 18th Division is to go to Malaya either direct or more probably via Bombay since very large United States ship in which it is embarked is unsuitable to go to Singapore and it would be without its guns and certain essential equipment. By transhipping at Bombay into suitable ships, the Brigade group should arrive complete with equipment at Singapore about 20th January.
(21) The position as regards the 17th (Indian) Division is as follows: - One Brigade Group was due to leave India for Malaya on 22nd December. A second brigade group with a squadron of light tanks (17 Mark IV) will be ready to leave very early in January, the tanks for Malaya and the group either for Malaya or for Burma as most required, the balance of the Division will proceed to Burma.
(22) One anti-tank regiment (48 guns), one heavy anti-aircraft regiment (16 guns) and one light anti-aircraft regiment (32 guns) in a convoy now at Durban are being diverted from Durban to Malaya. 50 light tanks from the Middle East are being sent to India as a general reinforcement for the Far East.
(23) It is proposed to increase the scale of defence at Indian Ocean naval and air bases and at Australian naval bases. Details are under examination. Meanwhile in addition to those mentioned above very considerable reinforcements of anti-aircraft guns, both heavy an light, are already en route or under orders for despatch within a month to the Middle East, Iraq, India and the Far East. A Royal Marine Anti-Aircraft Brigade (24 heavy and 16 light guns) is being despatched from the Middle East to Ceylon.
(24) The United States are being asked to examine the possibility of sending divisions to Northern Ireland with the object of releasing British formations for service overseas.
(25) The Commander-in-Chief, India , is being directed to put in hand administrative arrangements for the development of Rangoon as a base for a force which may ultimately reach four divisions and fifteen squadrons.
(26) General Chiang Kai-shek's offer of assistance in the defence of Burma has been gratefully accepted. Our military representation at Chungking has been strengthened and General Wavell himself is shortly going there for consultation with Generalissimo.
(27) The Commander-in-Chief has been instructed:-
(i) to recommend after consultation with the Dutch what land reinforcements are necessary in Java and Sumatra under the present conditions and in the event of Japanese occupation of Singapore.
(ii) to evacuate all unnecessary civilian personnel from Singapore.
(28) Air Force. Immediate preparations are being made to increase the strength of our air forces in the Middle East by the despatch of three torpedo bomber, half of one general purpose, three medium bomber, two heavy bomber and one long range coastal fighter squadrons in order to set off withdrawal of battle ships from the Eastern Mediterranean. The proposed programme of reinforcements cannot be fully completed for at least four months as our reinforcement line to the Middle East is already working to full capacity. Even with these additions our air forces in the Middle East cannot effectively replace battle ships in defeating the enemy sea borne operations so long as the western flank of our Mediterranean position can be threatened.
(29) One medium bomber squadron is being despatched immediately from the Middle East to Burma or the Far East and five more are to follow as soon as our operations in Cyrenaica admit.
(30) Twelve Blenheims from the Middle East have already been despatched to Singapore and some of these have already arrived.
Fifty Hudsons will leave the United Kingdom as soon as they have been modified and fitted with long range tanks: the first should arrive within three weeks.
(31) Fifty-one Hurricane aircraft, together with 18 Pilots and ground personnel of one fighter squadron and various technical equipment, now at sea in the vicinity of the Cape are being diverted direct to Singapore or the Netherlands East Indies as the situation demands. 32 Kittyhawk aircraft are being sent from Port Sudan to India or Singapore as soon as prepared.
(32) The ground personnel and equipment of three fighter squadrons now at sea in the vicinity of the Cape are being diverted from the Middle East to India for subsequent reinforcement of Burma and the Far East.
(33) We have instructed our Joint Staff Mission in Washington to press the. United States authorities to agree to go aircraft, together with appropriate personnel (which arrived on 19th December at Brisbane) being sent to Malaya or to the Netherlands East Indies should it not be possible for them to proceed to the Philippines.
(34) The United States authorities are being asked to examine the possibility of sending fighter and bomber squadrons to the United Kingdom to take part in operations and to release more of our squadrons for overseas.
(35) The Commander-in-Chief, Far East, has been asked to make recommendations as to the most urgent requirements of the Netherlands East Indies Air Force.
(36) We consider it essential to maintain the flow of air trainees from the Commonwealth and from New Zealand and methods of ensuring security of passage are being examined.
(37) The question of defence of Southern Pacific air route is being raised with the United States authorities. The latter have already taken steps to provide a light scale of defence at Canton and Christmas Islands but we doubt whether these are adequate.
(D) Note on the enemy course of action (38) Japan's object would appear to be to gain complete control and freedom of movement in the Eastern area by eliminating all allied power in that area. This necessitates capture of Singapore and Manila. The control of Netherlands area which would follow would provide Japan with certain vital economic resources, particularly oil.
(39) To this end, Japan appears to be directing her main attacks against Malaya, with a view to occupation of Singapore, and against the Philippines. The capture by the Japanese of Hong Kong would gain for them some strategic advantages but would not materially alter the strategic situation of the China Sea as a whole.
(40) The following operations might be carried out simultaneously with or independently of:-
(a) An attack on Sourabaya to destroy the Submarine Base.
(b) The repetition of attacks on Hawaii to impede repair of United States Naval Units and dockyards, so securing Japan from attack from the East.
(c) The occupation of Islands to give stepping stones in our Pacific air reinforcement route.
(d) Raids by cruisers, minelaying in ports and their approaches in Pacific Islands, Australia, New Zealand and India, attacks on shipping in the Pacific and Indian Oceans.
(e) The acquisition of refuelling bases in Madagascar.
(41) The following operations may develop from the main operations mentioned in paragraph (30):
(a) an attempt to occupy Sumatra and Java so as to close the entrance from the West into the China Sea.
(b) an attempt to occupy air bases in the Celebes and Halmahera.
I need not impress on you the vital secrecy of much of the foregoing information. Please treat it with the utmost discretion.