came in 1939 and the operational limitations of sonar were revealed, there was an
international consensus among naval experts that the maritime powers had little to fear
from the submarine in future warfare.
The air threat to sea power, both naval and commercial, was taken more seriously.
But in Britain, still the leading sea power, an influential school of thought believed that
ships could defend themselves against air attack. The Fleet Air Arm was relatively
neglected by the Navy, as it had also been while under the jurisdiction of the RAF, a
control that concluded as late as 1937. Certainly, the Navy had no intention of trans-
ferring its capital ship affection from the big guns of battleships and battle-cruisers to
aircraft carriers. The latter were held to be fatally vulnerable to attack by enemy surface
vessels and land-based aircraft.
The influence on strategic history of Britain’s evolving naval context in the 1930s
was considerable. If resistance were to be offered to German aggression, Britain was
the key strategic player in the second half of the decade because France would not move
on its own. Paris knew that it could succeed in a new war with Germany only if Britain
was a reliable ally. The maritime dimension to Britain’s foreign policy in the 1930s was
of fundamental importance yet became ever less permissive of British discretion in
policy and strategy. Britain’s standing and capabilities as a great power rested in good
part upon its sea power. But in the 1930s that sea power was menaced by the reality of
an impressive-looking Italian fleet in the Mediterranean, by an aggressive Japan that
formally exited the Washington–London naval arms limitation regime in 1936, and by a
new German Kriegsmarine which, though still modest in scale, was high in quality,
certain to grow larger and, moreover, based perilously close to British home waters.
Britain’s theory of victory in a future war with Germany, a theory shared with the French,
depended utterly upon Allied command of the seas. The Anglo-French intention in
1939 was to draw Germany into a long attritional war wherein the balance of resources
would prove decisive, as it had in 1914–1 8. The theory made strategic sense in its own
terms only if the Allies controlled the sea lines of communication essential to their
mobilized war effort. British statecraft in the 1930s thus was exercised in a strategic
context perceived at the time to contain twin lethal dangers. On the one hand, Britain
faced catastrophe from the air. On the other, the diplomatic linking of Germany, Italy and
eventually (1940) Japan posed a potentially fatal maritime threat to the integrity of
British, and hence Allied, strategy altogether.
Disarmament for land and air forces proved thoroughly non-negotiable at the League’s
Disarmament Conference in 1932–4. But naval disarmament had registered some major
achievements much earlier, principally at a conference held in Washington in 1921–2,
and at a long-delayed follow-up conference in London in 1930. The Washington and
London treaties imposed a ten-year building ‘holiday’ on the construction of capital
ships (battleships and battle-cruisers), subsequently extended for another five years; a
5:5:3 ratio between Britain, the United States and Japan in capital ship and aircraft-
carrier displacement, extended in 1930 to include cruisers, destroyers and submarines; a
35,000-ton limit on capital ship displacement and a 16-inch calibre limit on main
armament; and a prohibition on the further fortification of naval bases in the Pacific, with
Singapore excluded on British insistence. These were the major provisions, but the
full strategic context for the discussion of naval disarmament was complicated by the
distinctive geostrategic situations of each country, as well as by the regional interests of
120 War, peace and international relations