289 Mr A. Eden, U.K. Secretary of State for Dominion Affairs, to Mr R.G. Menzies, Prime Minister

Cablegram unnumbered LONDON, 12 October 1939, 11.27 p.m.

MOST SECRET PERSONAL

Following for Prime Minister- In reply to request recently received for advice 'as to military position which would be created in the event of Russia declaring war and cooperating with Germany in military action", following appreciation has been prepared:-

2. It should be stated at the outset that His Majesty's Government in the United Kingdom consider it unlikely that Russia will adopt this course, for the following reasons:-

(1) She is in process of realising her ambitions in the Baltic, has barred Germany's path to Roumania and the Black Sea, has extended her influence in South Eastern Europe, and, acting through Turkey, will probably be able to exclude the naval forces of other countries from the Black Sea. AU this has been achieved without war and its accompanying risks.

(2) Her abiding aim is to spread world revolution. To achieve that object her policy is likely to be to induce Germany and other countries to exhaust themselves in war while herself remaining outside the struggle. (3) Too close a co-operation between Russia and Germany is likely to antagonise Italy, Spain and Portugal, and thus to encourage the building up against Russia of a new political coalition.

3. Assuming that, despite the above, Russia decided to fight on Germany's side, the salient features of the military position which would arise are summarized in the paragraphs that follow:

4. At sea, submarine warfare would probably be intensified in home waters. More determined action by German surface vessels would have to be expected, and the availability of the ice-free port of Murmansk would broaden the base of the enemy's operations. A minor threat to British trade might develop in the Pacific.

5. On land and in the air, direct military co-operation with Germany seems unlikely on any appreciable scale. Germany already has large land forces and a preponderance in aircraft, and there would be political dangers in the acceptance of Russian troops on German soil. Russia might, however, supply some technical troops and certain types of aircraft for use on the Western Front.

6. In the economic sphere, Russian support would slow up the effect of our economic pressure on Germany, who might feel she could afford to play a waiting game on the Western Front in the hope that the pressure of neutral opinion and of our own people would compel us to make peace while her military strength was still unimpaired. At the same time, any economic assistance which Russia might render to Germany would correspondingly restrict her own military activities and vice versa.

7. Russian propaganda, which is an immediate menace to our interests, would be excessive, particularly in the Middle East. By the use of this weapon, combined with military action, she could cause us serious embarrassment by locking up allied forces in the secondary theatres, and in particular Iran, Iraq and Afghanistan.

8. So far as Iran is concerned, Russia could easily penetrate both with propaganda and with small military forces into the northern provinces, and such penetration might develop into a threat to Anglo-Iranian oilfields, which we should have to resist.

9. Russian penetration in Iran would of itself cause disturbances in Iraq, and a further advance would threaten the Mosul oil fields and our overland communications from the Persian Gulf to Egypt. We should be bound to resist any such advance.

10. Russia might, without any great military effort-(1) Absorb the northern provinces of Afghanistan; and (2) Launch light scale air attacks on India itself The general effect in India of the near approach of Russian menace might be to rally all classes of Indians in the prosecution of the war, though it has to be remembered that there is an appreciable Communist element in the Left Wing, the most powerful political party in India, which looks to Russia for inspiration, and that Russian propaganda might therefore have unfortunate repercussions in India itself On the other hand, (i) above would make it difficult for the Afghanistan Government to maintain its position, and unless we could assist it to do so there would almost certainly be serious tribal disturbances on both sides of Indo Afghan communications; while (2) might create considerable demoralisation in the unprotected cities of Northern India and thus complicate the internal security problem.

In either event no reinforcements could be drawn from India. On the contrary there might be calls from India for land and air reinforcements particularly the latter.

11. Unless Italy were a definite friend, the despatch of adequate forces particularly air forces to Iran, Iraq and India would be extremely difficult, (but see paragraphs 2 and 14).

12. Even if Russia did not openly fight on Germany's side but were benevolently neutral towards her, many embarrassments summarised in paragraphs 4 to 10 would operate though in some cases to an extreme extent.

13. It will be seen from the above that a close association between Germany and Russia would have serious military implications. On the other hand this association can be bought by Germany only by sacrificing German interests in the Baltic and South East Europe. This may well lead to a revulsion feeling in Germany which may bring the Russo-German antagonism to the surface sooner than Herr Hitler intends.

14. In many quarters particularly the Mediterranean area the United States of America and in the Roman Catholic countries generally the Russo-German agreement is likely to influence sentiment in our favour. In short we may later be in a position to mobilize the world opinion to rally to Christian front as against anti-Christian forces.

15. This appreciation is being telegraphed also to the other Prime Ministers.

1 Document 255.

[AA: A1608, A41/1/1, v]