British strategic foreign policy did not begin when war broke out on 4 September 1939. As we have seen, broad views of what would become the major neutrals had become established at the Foreign Office throughout the interwar period. However, what needs to be determined is how each of these neutrals was factored into British defence policy, particularly in the eight months before the war began, in order to appreciate what occurred when hostilities broke out.

Throughout the 1930s, Italy was important for British defence planning for a variety of reasons. First, Rome's determination to make the Mediterranean an Italian lake threatened British lines of communication to the Far East. The keys to preventing this were good diplomatic relations with Italy, and, barring the former, a strong British naval presence at Malta and in the Mediterranean generally. Second, Italy's desire to expand her colonial empire in Africa threatened Britain's position in Egypt and acted to destabilise the region. The Italian invasion of Abyssinia in 1934 in particular created difficulties for British imperial defence. Finally, beginning in 1936, the Italian participation in the Spanish Civil War not only caused strains in Anglo-Italian diplomatic relations but also caused Rome's relations with Paris to sour further. Therefore, French defence planning had to take Italy as well as Germany into consideration, particularly with respect to naval and imperial matters. For Britain, this French preoccupation meant that any attempt to improve relations with Italy (or to check her by military means) had to be done with thoughts of how this might redound on Anglo- French relations, further complicating strategic foreign policy.

The situation was clearer with respect to Japan. Since 1931, Tokyo had been militarily active on the Asian mainland, threatening the British position in the Far East. The failure of the League of Nations to contain Japan had left London in a difficult position. Opinions in Whitehall about how to deal with Japan were varied, with the Treasury favouring an Anglo-Japanese rapprochement and the Foreign Office opposing such a move. Much of this difference centred on naval matters. British defence planning in the Far East was built around the so-called ‘Singapore strategy’.