In connection with Mr. Churchill's cable No. 219  4th July, that proposal for a British Commonwealth Land Force to take part in the operations against the main Japanese Islands has reached only an exploratory stage as the details of the American plan for assaulting the main Japanese Islands are not known here. It is intended to proceed with detailed planning with the Americans and with the Dominions involved if the offer is accepted in principle at the forthcoming Conference in Berlin. In the meantime it might be helpful if I give you some of the thoughts on detail on which I understand the United Kingdom proposal has been based.
1. It is expected that future operations in the Malayan area will lead to the capture of Singapore and the opening of the Straits of Malacca by November, 1945.
2. The British Chiefs of Staff expect to accept responsibility for the area offered by the Americans after the capture of Singapore when Admiral Mountbatten will be in a better position to control his part. It is thought that the Australian Chiefs of Staff may wish to take over their part of the area by mutual agreement with General MacArthur at any convenient time after the proposal to transfer the area to British Control has been agreed to.
3. The proposed dividing line east of the Celebes is tentative.
Admiral Mountbatten will need to plan first for clearing the main Dutch Islands west of the proposed boundary and for the time being he can do nothing about the eastern half of the Netherlands East Indies. The Australian services know the area and are in a better position to have control of it. It is not intended that this should automatically involve the Australian Forces in any new commitments for offensive operations, and it is thought that alterations by mutual agreement will be desirable when detailed plans for clearing the Netherlands East Indies are drawn up.
4. Operation against the main Japanese Islands in which a British Commonwealth Land Force may take part is not likely to begin before March, 1946. I am not aware of our expectation of a date for a successful conclusion of the operations in Borneo but there should be sufficient time before March, 1946, for rearrangement, if necessary, and reorganisation if you decide to use troops in Borneo for the proposed task. The arrangements for linking up the Australian Division with the rest of the Force will, of course, be a matter for subsequent planning. The main Force is expected to assemble in India. It is not intended that the Australian Division will join them there but that they would leave for a forward rendezvous direct from the Australian area.
5. The Force will need a Tactical Air component of some fifteen squadrons and again subject to detailed planning it is hoped that Australia and New Zealand will be able to provide most of this contingent.
6. You will realise that this information should be treated with great discretion. Admiral Mountbatten has not yet been told of the proposal and is expected to be given a directive on the matter after the Conference in Berlin. He is paying a visit to General MacArthur almost immediately (not via Australia) but is not to discuss at this meeting plans for the final stage of the war against Japan.
In view of the Big Three meeting it would be most helpful if you could reply not later than 15th July.