42 Report by Chiefs of Staff Sub-committee of Committee of Imperial Defence on Questions raised by Australian Delegation to Imperial Conference
Extracts LONDON, 9 June 1937
The Australian Delegation has submitted a number of defence
questions for consideration at the Imperial Conference. These
questions are contained in the following papers:-
Paper No. 1, C.O.S. 580.-British policy in the Far East.
Paper No. 3, C.O.S. 581.-Priority of provision for defence and
rate of provision.
Paper No. 4, C.O.S. 582.-Defence against invasion and its
reactions on priority.
Paper No. 5, C.O.S. 583.-Defence against raids and its reactions
Paper No. 5A, C.O.S. 584.-Defence of Port Darwin.
In addition, further questions which need to be considered in
conjunction with the above papers are raised in:-
Paper No. 7.-The type of Squadron for the Royal Australian Navy.
Paper No. 8.-Strategical Naval Wireless Stations.
Paper No. 11.-The Royal Australian Air Force-organisation,
priority of development and equipment.
2. In the following pages we review the problems raised by the
Australian Delegation and formulate our answers to their
BRITISH POLICY AND STRATEGIC OBJECT IN THE FAR EAST
BRITISH POLICY IN THE FAR EAST
3. The Commonwealth Government have submitted a series of
questions on the political aim in peace of the United Kingdom
foreign policy in the Pacific region. The Foreign Office has
drafted answers to these questions; and questions and answers are
set out in the following paragraphs:-
4. What are the guiding considerations in British policy for the
realisation of the aim of permanent friendship with Japan?
What is their relation to the maintenance of British interests in
China in view of Japan's penetration in Asia and her claim to a
special position in the Far East, which amounts to the dictation
of the conditions under which she will co-operate in Chinese or
His Majesty's Government in the United Kingdom naturally aim at
the establishment of the friendliest possible relations with Japan
and the adjustment of differences that exist between the two
countries, but not at the expense of China or at the expense of
their good relations with China, on the maintenance of which
British interests depend.
They cannot be openly associated with a Japan that adheres to the
policy which Japan has in recent years followed in regard to
China. Happily there are signs that Japanese policy has taken a
new direction, and His Majesty's Government may therefore now work
in a more hopeful spirit for an improvement of the general
situation in the Far East.
5. Is the present policy of accommodation to Japan a temporary one
pending the strengthening of British defences, and does the United
Kingdom Government propose to stiffen its attitude when its
rearmament is complete?
His Majesty's Government's hope is for permanent friendship and a
harder attitude in the future is not in contemplation.
6. Is the United Kingdom Government prepared to go to war in
defence of its interests in China and Hong Kong?
His Majesty's Government in the United Kingdom are certainly
resolved to defend to the utmost of their ability British
interests in China and Hong Kong. It is, of course, impossible to
say beforehand what circumstances or what degree of menace might
lead His Majesty's Government to consider that a resort to arms
was necessary for their defence.
7. In the opinion of the United Kingdom Government, is the
maintenance of the integrity of the Netherlands East Indies vital
to the security of Singapore and the scheme of defence of Empire
interests that hinges on this base?
The importance of maintaining the integrity of the Netherlands
East Indies has recently been emphasised by the Committee of
Imperial Defence in the following terms:-
'That the integrity of the Dutch East Indies was a major British
interest, but in existing conditions it was inadvisable to
8. To what degree is British policy in harmony with that of the
United States on matters relating to Asia and the Pacific region
General harmony appears to exist, but there is nothing in the
shape of a definite agreement apart from the Nine-Power Treaty.
9. If a firm stand is taken, to what extent can the United States
be relied on for co-operation in view of-
The general American attitude of isolation from the League, even
where they may have special interests, as in the Sino-Japanese
dispute in 1932-33 ;
The desire to maintain neutrality as indicated by the recent
legislation by Congress ;
The independent attitude revealed by their unwillingness to renew
Article XIX of the Washington Treaty ?
Nothing specific can be relied upon from the United States of
(All the above questions ate contained in paragraph 11 of Paper
BRITISH STRATEGIC OBJECT IN THE FAR EAST
10. The Commonwealth Government asks for a clear definition of the
strategical object of the Empire forces in a war with Japan or
with Japan and another first-class Power. (Paragraph 13 of Paper
11. In the following paragraphs we outline the policy which should
govern the conduct of a war with Japan-
(a) When we are at peace in Europe, but must retain in Home waters
a Fleet sufficient to neutralise the German Fleet.
(b) When we are already engaged in war with Germany before
Japanese aggression occurs.
WHEN WE ARE AT PEACE IN EUROPE, BUT MUST RETAIN IN HOME WATERS A
FLEET SUFFICIENT TO NEUTRALISE THE GERMAN FLEET
The basis of our strategy lies in the establishment of our Fleet
at Singapore at the earliest possible moment after the outbreak of
hostilities. Our own security and our ability to bring pressure to
bear upon Japan are equally dependent on this action. It is,
therefore, of paramount importance that the Singapore base should
be available on the arrival of our Fleet. To ensure this,
reinforcements must be moved to Singapore and the security of
their routes safeguarded upon any state of tension developing.
In addition, all measures necessary for the security of our
defended ports and our air and other routes to the Far East must
be put into operation.
Before the arrival of our fleet at Singapore we should, where
necessary, rely on evasion for the security of our commerce, and
upon local defences for the security of out ports and territories,
coupled with operations against the raiders by the forces
immediately available. Once our main fleet is in the Far East we
should rely on its presence to give adequate security to our
Although our situation at Hong Kong is inherently weak, we should,
as long as our policy is to hold the fortress, take any
opportunity to reinforce the garrison during a period of strained
relations, but not at the expense of reinforcements considered
necessary for the security of Singapore.
Although we cannot foretell what the situation will be when the
British Fleet arrives at Singapore, it is clear that, so long as
Hong Kong is still holding out, the Fleet will be required to go
forward either to reinforce or to evacuate the garrison. The
decision as to which course of action is to be adopted must be
made at the time in the light of all information then available.
The attitude of China will be an important factor in this
situation, and we must from the outset take all possible steps to
encourage the Chinese in active hostility to Japan. At the same
time, we must so restrict our action in China as to avoid any
liability of becoming involved in major land and air operations.
We must primarily rely upon the exercise of economic pressure to
enable us to defeat Japan. With our Fleet based at Singapore or at
any base further north, the restrictions which we could impose on
Japanese trade give good prospects of breaking Japanese powers of
resistance in the course of two years provided that at the same
time we can sever her trans-Pacific trade. To this end, in
addition to our naval operations, we should do all that is
possible to enlist the sympathy and assistance of America.
A successful fleet action is our only apparent means of forcing an
earlier decision. Not only would this give us complete control of
sea communications, but the psychological effect on Japan might
well be such as to force her to make terms. The decision to seek
or decline a fleet action must rest with Japan. Our policy,
therefore, should be to seek a fleet action under adequately
favourable conditions and, as a corollary, to avoid exposing the
fleet to any serious risk of attrition.
While this war will make very full demands on all our naval
resources, and may continue for two or three years, the policy
which we recommend does not visualise the employment of army or
air forces on a national scale.
WHEN WE ARE ALREADY ENGAGED IN WAR WITH GERMANY BEFORE JAPANESE
Our policy for a war against Japan would remain unchanged except
in the following respects:-
During the period immediately following the outbreak of war with
Germany and before the outbreak of war with Japan, we should
immediately avail ourselves of the opportunity of carrying out
preparatory measures in the Far East without interference by
At Singapore we should, during this period, not only put into
effect the existing reinforcement plans, but should also increase
the reserves of supplies to the maximum extent possible.
We should concentrate our outlying battalions from North China at
Hong Kong, but should send there no further reinforcements except
those necessary to enable the existing fixed defences to be manned
adequately. We should also increase the reserves of supplies at
Hong Kong. Although we cannot, in this case, rely on our fleet
being able either to reinforce or to evacuate our garrison at Hong
Kong once war has broken out with Japan, our policy would still be
to hold Hong Kong as an outpost for as long as possible.
Once war with Japan has broken out, our policy must be governed by
the consideration that, until the issue with Germany has been
settled, we cannot count on being able to support anything more
than a defensive policy in the Far East. Economic pressure would
remain the essential feature of this policy, but owing to the
heavier demands on our naval forces its action is bound to be
EFFECT UPON OUR POLICY OF INTERVENTION OF THE U.S.S.R. OR ITALY
It seems unlikely that Soviet intervention on our side would
introduce any serious change in our policy for war in the Far
The intervention of Italy against us would at once impose
conflicting demands on our fleet.
In this situation our policy must be governed by the principle
that no anxieties or risks connected with our interests in the
Mediterranean can be allowed to interfere with the despatch of a
fleet to the Far East.
DEFENCE AGAINST INVASION
12. The Commonwealth Government asks to be furnished with a
strategical appreciation of the danger to Australia of invasion
and the defence against same, in the light of the naval situation
and the security of the Singapore Naval Base and line of
(a) For the period up to 1942.
(b) After 1942.
The Commonwealth Government also wishes to know whether, in
certain circumstances (the reasonable probability of which might
be indicated), it would be possible for Japan to undertake major
military operations with an object and on a scale amounting to
invasion, against Australia. The probable form and scale of such
an attack might be stated. They also wish to know the probable
period of warning that might be available for completing
preparations for defence after the first obvious indication of a
threat of war. (Paragraph 10 (i) of Paper No. 4.)
DEFINITION OF INVASION
13. Invasion implies an attack by a force which is landed with the
intention of prolonged or even permanent occupation of the
territory invaded, and which is dependent for success on the
maintenance of a line of communications.
We, therefore, assume that the invasion of Australia by Japan
implies the establishment and maintenance of Japanese military
forces in Australia on a scale sufficient to enable them to
undertake operations with the object of eventually overcoming all
Australian resistance and forcing Australia to sue for peace.
INVASION AND THE NAVAL SITUATION
14. In war, the fate and future of oversea territories has always
been decided by the outcome of the war in the main theatre. In a
Far Eastern war the fate of British Commonwealth territories in
the East will be decided on the outcome of the struggle between
the British Commonwealth and Japan for the control of sea
This is a fundamental truth which has not changed, and it has in
the past been reflected in the strategic disposition of Dominion
navies in war plans.
15. A change has, however, taken place in the scale of
preparations and the scale of armaments necessary for oversea
expeditions. These are much greater to-day than formerly owing to
the greater complications in war material, the more varied
composition of armies and the fact that an expedition must be
prepared on arrival at its objective to meet and overcome the
shore-based air forces of the defence. A large expeditionary force
requires to-day a large fleet of ships of all types, and these
must be followed by a continual stream of war material. In a Far
Eastern war even the Commonwealth of Australia, the Dominion
nearest to Japan, is still so far distant that no Japanese
Government could face the responsibility of committing a large
expeditionary force for service in Australia unless the command of
the sea line of communication was assured for a sufficient period
to enable the object to be achieved.
In the opinion of the General and Air Staffs an invader must, in
addition, be confident of being able, on arrival, to operate air
forces adequate to ensure air superiority during the landing and
subsequently to protect the expedition and its reinforcements and
supplies on arrival at their destination, against action by the
air forces of Australia. It is not considered possible to
establish such air superiority with ship-borne aircraft against
adequate land-based aircraft in so large a country as Australia.
16. A Japanese overseas expedition aimed at Australia may
consequently be said to be a highly improbable undertaking so long
as our position at Singapore is secure, and the fleets of the
British Empire are maintained at such a strength as to enable a
force capable of containing the Japanese fleet to be despatched to
the Far East, should the occasion arise. We propose, therefore, to
examine the question of the strength of the fleet that we can send
to the Far East, and the time required for its arrival in that
area, in the event of war with Japan.
17. In order to relate our examination to the practical political.
conditions of the world as they exist at present, we propose to
consider war against Japan in the following cases:-
(a) When we are at peace with Germany, but must retain in home
waters a fleet sufficient to neutralise the German fleet.
(b) If war with Japan breaks out when we, allied with France, are
already at war with Germany.
We will then briefly outline the possible effects of intervention
by the U.S.S.R. and Italy.
WHEN WE ARE AT PEACE WITH GERMANY, BUT MUST RETAIN IN HOME WATERS
A FLEET SUFFICIENT TO NEUTRALISE THE GERMAN FLEET
Strength of fleet for Far East
18. The strength of the fleet that we could send to the Far East
must be governed by consideration of our home requirements. In the
new standard of naval strength we would aim at:-
(i) Placing a fleet in the Far East fully adequate to act on the
defensive, and to serve as a strong deterrent against any threat
to our interests in that part of the globe.
(ii) Maintaining in all circumstances in home waters a force able
to meet the requirements of a war with Germany at the same time.
NOTE:-Included in (i) and (ii). would be the forces necessary in
all parts of the world behind the cover of the main fleets, to
protect our territories and merchant ships against sporadic
attacks. 19. When considering what naval strength we must retain
in home waters as a counter to Germany, we might count on France
as an ally in the event of war actually breaking out. In their
Annual Review for 1935 the Chiefs of Staff stated: 'Although His
Majesty's Government in the United Kingdom would never, we
presume, confide the entire protection of this country (i.e., the
United Kingdom) and its vital sea communications to a foreign navy
in the absence of our main fleet, yet if France were our ally, her
naval forces could undertake part of this responsibility. A
British capital ship, cruiser and destroyer strength in home
waters equal to that of Germany is probably the least we could
accept.' On this basis we review below the situation as regards
our heavy ship strength vis-a-vis Germany and Japan.
20. The following table shows a provisional allocation of heavy
ships between the Home and Far Eastern Fleets during the next
three years to meet the increasing German Navy and the nine
modernised heavy ships of Japan. The withdrawal for modernising of
three of our heavy ships introduces an element of weakness in the
situation, particularly from the spring of 1938 to the summer of
1939, but even during this period we can regard our Far Eastern
Fleet as at least equivalent in fighting value to the Japanese
HEAVY SHIP STRENGTH AVAILABLE TO MEET THE GERMAN FLEET AND NINE
MODERNISED JAPANESE HEAVY SHIPS
Period German Fleet Our Fleet at Home Our Far Eastern
Fleet Out of action (modernising)
Summer 1937 to Spring 1938 3 Deutschlands Hood Repulse
2 Nelsons Warspite (fully modernised) Malaya, Royal Oak
(partly modernised) Barham 4 Revenges (unmodernised) Total: 10
ships Renown Valiant Queen Elizabeth
Spring 1938 to Summer 1939 3 Deutschlands 2 Scharnhorsts Hood
Repulse Malaya Barham 2 Nelsons Warspite Royal Oak 4 Revenges
Total: 8 ships Renown Valiant Queen Elizabeth
Summer 1939 to Spring 1940 3 Deutschlands 2 Scharnhorsts 2
35,000 ton battleships* Hood Repulse Renown 2 Nelsons 3 Warspites
Malaya Royal Oak Barham 4 Revenges Total: 10 ships
* 1 at the end of 1939; 1 in the spring of 1940
Although it will be seen from the above table that our battleship
strength will be at a low ebb in 1939 compared to Germany and
Japan, at no time up to 1940 will we be unable to send a fleet to
the Far East; and with the completion in 1940 of five new
battleships (already laid down) for this country the period of
weakness will be past, provided we retain all our existing ships
and the crews to man them.
21. As regards classes of ships other than heavy ships, the
numbers available will vary according to the year in which war
breaks out. Taking conditions in 1939, we might retain at home two
Aircraft Carriers (excluding 1 for training and 1 refitting), six
8-inch and twelve 6-inch cruisers, and four destroyer flotillas.
This would leave available for the Far East and trade protection
four aircraft carriers, seven 8-inch and forty-eight 6-inch
cruisers and five destroyer flotillas. When the demands for
cruisers to work with the fleet have been met, there will be a
shortage of cruisers for the protection of our own trade and
action against that of Japan. In these circumstances, we shall
have to rely largely on the seventy-four armed merchant cruisers
to be taken up on the outbreak of hostilities. It appears most
improbable that we shall be able to spare any aircraft carriers
for operations on the trade routes.
PASSAGE OF FLEET TO FAR EAST
22. As regards the time of arrival of the fleet in the Far East,
for the actual passage from home waters and the Mediterranean, the
combined Home and Mediterranean Fleets would require 28 days to
reach Singapore via the Suez Canal and Malacca Straits. If the
Sunda Straits are used, an extra 2 days must be added. If the
fleet has to use the Cape of Good Hope route, the passage time
would be 45 days. Apart from passage time, however, an allowance
of 10 days must be made for preliminary preparations, and is days
for possible fuelling delays and weather conditions en route.
Plans for the necessary fuelling arrangements on passage have been
made by the Admiralty. Hence, the maximum time that must be
allowed for the arrival of the fleet at Singapore is 70 days.
IF WAR WITH JAPAN BREAKS OUT WHEN WE, ALLIED WITH FRANCE, ARE
ALREADY AT WAR WITH GERMANY
Our naval situation
23. Our naval situation will be largely governed by the time at
which war with Japan breaks out, and the action which the German
naval forces have taken up to that time. In the best case, war
with Japan might not occur until our naval resources had been
fully developed, while German naval forces had acted entirely on
the defensive, being held back in the Baltic and North Sea. In the
worst case, war with Japan might occur before our naval resources
had been fully developed, while German naval forces had assumed a
vigorous offensive against our trade in the Atlantic, and possibly
elsewhere. The time at which we can send a fleet to the Far East,
and its strength, will depend upon the conditions which have
actually arisen. Again, as shown in paragraphs 20 and 21 above,
the year in which war breaks out will also determine the
allocation of naval forces between the European and Far Eastern
theatres. We are thus faced with many varying factors, and can
only endeavour to make some general deductions.
24. To take a probable situation in the European theatre, our
naval forces may be operating at strength in the Atlantic,
considerably dispersed. French battle cruisers may be assisting in
these operations, while a proportion of our heavy ships may be
assisting with French African convoys. If, in these circumstances,
we have to deal with Japan, a very considerable period may elapse
before the progress of our operations against Germany and the
redistribution of our forces permit of a fleet arriving in the Far
25. Thus, the strength of the fleet for the Far East, and the time
within which it would reach Singapore, must be variable factors,
dependent both upon naval and political considerations.
Nevertheless, the basis of our strategy will lie in establishing
at Singapore, at the earliest possible moment after the outbreak
of hostilities with Japan, a fleet whose strength, as a minimum,
will enable it to act on the defensive and to serve as a strong
deterrent against any threats to our interests in the Far East.
THE PROBLEM OF INVASION FROM THE JAPANESE POINT OF VIEW
26. It may be of value now to examine the problem of invasion as
it might appear to Japan. Although in the absence of the British
main fleet from the Far East Japan can obtain control of sea
communications, she must take into account the possible presence
and operations of our China, East Indies, African, Australian and
New Zealand naval forces, amounting to seven 8-inch and nine 6-
inch cruisers, one aircraft carrier, fourteen destroyers and
fifteen submarines (June 1937). So long as these forces, or a
proportion thereof, are in being, Japan will have to take adequate
naval measures for the security of the passage to Australia of her
expeditionary force, and for its maintenance and reinforcement.
This operation to be successful, would necessitate the defeat not
only of the Australian army, having in mind the great power of
defence in modern warfare, but also the air forces of Australia,
which by 1939-40 will amount to a total of twelve squadrons
27. To estimate the probable size of the initial expeditionary
force sent to Australia from Japan, its point or points of
landing, the scale of its reinforcements, and the subsequent
military operations in Australia, would demand an extensive
appreciation, which might best be prepared by the Australian
General Staff and Air Staff. It is noted that the Australian
General Staff consider that the Japanese political object might be
achieved most readily by the capture of Sydney and/or Melbourne,
possibly preceded or accompanied by hostile air attack on those
cities. The capture of cities, however, presents a problem of
considerable military difficulty, and would not, in our opinion,
be of itself necessarily decisive.
28. Without making a detailed appreciation it appears reasonable
to assume that Japan would not undertake the initial act of
invasion with a land force of less than two divisions as an
This would necessitate about 400,000 tons of shipping or from 40
to 70 ships. From Japan to Sydney is a distance of 4,400 miles.
From the Pelew Islands, where the force might be assembled, to
Sydney is a distance of about 3,000 miles.
In view of our remarks in paragraph 26 above, Japan, despite her
initial superiority in the Far East, would be faced with a
considerable naval commitment in escorting, maintaining and
reinforcing such an expedition.
In view of our remarks in paragraph 15 above, it is clear also
that Japan would be faced with a considerable air problem; and if
she relied on ship-borne aircraft she could not hope for air
29. Assuming the successful landing of the expedition in the
vicinity of Sydney or Melbourne, Japan would have to establish
herself in sufficient depth to build up her forces for her
subsequent operations. The length of the communications between
Japan and Australia, and the necessity for their protection,
militates against the rapid reinforcement of her initial
expedition. It is difficult to see how Japan could build up in
Australia an adequate force to embark on operations on the
necessary scale in any period under six months. In effect, Japan
would require to be certain of ample time if she hoped, by means
of invasion, to force Australia to sue for peace.
30. Japan, however, can never be certain of being allowed time.
She cannot prevent the passage of a British fleet to the Far East,
nor rely on circumstances being or remaining such as to prevent
its despatch. With a British fleet established at Singapore, and
operating therefrom against the Japanese lines of communication
with Australia, the whole position of the Japanese invading forces
in Australia would become precarious, unless Japan could
decisively defeat the British fleet. It is in the highest degree
unlikely that Japan would engage upon operations for whose success
she would have ultimately to rely on a decisive victory in a fleet
action fought under conditions not of her own choosing and
possibly disadvantageous to her.
31. In effect, if Japan wishes to ensure time for the invasion of
Australia, she must endeavour to prevent the British fleet from
operating in the Far East; one means to this end would be for
Japan to capture Singapore. The defence of Singapore has been
fully examined, and the main conclusion drawn was that deliberate
operations held out the best hope of success for Japan. These,
however, required time, and though the possibility of such
operations could not be definitely excluded, it appeared unlikely
that the Japanese would undertake them even if a 60 to 70 days'
delay in the arrival of the British main fleet could be
This conclusion was based on the fact that Japan can never exclude
the possibility of having to fight a fleet action in the Singapore
area in support of her deliberate operations against Singapore;
and, as in the case of the invasion of Australia, Japan would be
in the highest degree unlikely to commit her forces to an
operation for whose ultimate success she might have to rely on a
decisive victory in a fleet action fought under conditions, in
this instance, certainly disadvantageous to her.
Even if Japan captured Singapore, she could not absolutely rely on
preventing operations in the Far East by the British Fleet,
despite the great difficulties with which it would be faced in
32. To sum up, apart from the magnitude of the task involved in
any effort to overcome the military and air opposition to her
landing and subsequent operations in Australia, Japan, from the
strategical point of view, would be unjustified in committing
large military and air forces to such an operation unless the
British Fleet had first been defeated and largely destroyed.
INTERVENTION OF THE U.S.S.R.
33. The intervention of the U.S.S.R. against Japan would involve
Japanese land and air forces in major operations in Manchukuo and
the countries round the Sea of Japan. In these circumstances the
possibility of Japanese action against Singapore, or to invade
Australia, would become even more remote than under the conditions
INTERVENTION OF ITALY
34. The intervention of Italy against us would at once impose
conflicting demands on our fleet. In this situation our policy
must be governed by the principle that no anxieties or risks
connected with our interests in the Mediterranean can be allowed
to interfere with the despatch of a fleet to the Far East.
35. With the naval forces of the British Empire at their present
strength, and maintained in the future at the standard laid down
in paragraph 18, His Majesty's Government in Australia need not
regard the danger of invasion as a real one.
SCALE OF RAIDS AND REVIEW OF PROGRESS IN FIXED DEFENCES
42. The Commonwealth Government asks advice on the validity of
assuming the arrival of the British main fleet at Singapore with a
minimum delay after the outbreak of war in the Far East.
(Paragraph 10 (iii), Paper No. 5.)
43. This question has been fully covered in Part II of this paper.
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