372 Mr R. G. Menzies, Prime Minister, to Lord Caldecote, U.K. Secretary of State for Dominion Affairs
Cablegram 290 13 June 1940,
MOST IMMEDIATE MOST SECRET
Your Z. 104  arrived when my Government was considering a revised appreciation which the Chiefs of Staff had been requested to submit urgently regarding the needs of local defence and the further resources which are available for offer to the United Kingdom. 
The quick deterioration of the situation renders it difficult to establish a reasonably firm basis for vital decisions governing war policy and the same considerations have no doubt handicapped your advisers in furnishing the review asked for in my cablegram 208 of 8th May. 
My Government feel, however, that such information covering the probable alternatives with which the Empire may be confronted is of the greatest possible urgency to enable us to review our policy on local defence and Empire co-operation and to decide on the measures necessary to give effect to it.
Under certain contingencies it might be possible to render- (a) Further naval assistance such as one armed merchant cruiser.
One sloop at once and an additional sloop at the end of July for use in the Indian Ocean and Red Sea area.
(b) Subject to contingencies as mentioned, which it will no doubt be possible to judge by the review asked for, additional assistance might be rendered with further land forces, but the governing factors appear to be advice as to the theatre in which they would be employed and capacity to equip and ship them within the time required. In regard to equipment, as mentioned in my cablegram 256 of 3rd June  the subject is under discussion between the High Commissioner and War Office and matter is vitally affected by practicability of shipment and what is in view in this respect should Red Sea route be closed. In a separate cable we are advising the High Commissioner  that we will render the maximum possible effort from our own resources and informing him of the immediate requirements we are able to provide.
(d)  Similarly, it might be possible to make available from the Air Force one extra Squadron of Hudsons and one Squadron of Wirraways. In view present armament of Hudsons and Wirraway aircraft which is peculiar to Australia these units could more profitably be employed on replacing R.A.F. units in India or Far East preferably Singapore where we are already sending one Hudson Squadron.
I would repeat my earlier assurance that the Government and people of Australia are fully behind you in the resolve to defend the Empire until victory is assured.