Historians have given widely different interpretations of Chamberlain’s offer of a guarantee to Poland and of its significance. The evidence for Chamberlain believing it was no longer possible to deal with Hitler on the same basis as at Munich is examined, as is the evidence that the prime minister was increasingly constrained in foreign policy by public opinion, which had come round to Churchill’s position on appeasement. Churchill urged a reluctant Chamberlain to back the guarantee with an Anglo-Franco-Soviet Alliance, and the prime minister has been much criticised for failing to do so. The failure is explained with reference to intelligence assessments of Soviet capability and reliability and also to Soviet demands in the negotiations and to Stalin’s decision to opt for a pact with Hitler. The significance of Chamberlain’s secret contacts with Germans and Swedes in the summer of 1939 is explored. Chamberlain’s conduct in the final crisis in August and September is considered in the light of claims made then and also by some historians that he was forced by the House of Commons into declaring war.

Hitler’s seizure of Austria heightened awareness of the international danger. Churchill pointed to the weakening of France’s Eastern European alliances, but was deterred from advocating the use of force to reverse Hitler’s action by fear of air attacks on London. Instead he called for greater RAF expansion, and the government took steps to maximise aircraft production, including allowing rearmament contracts to divert industry from civil trade. On the other hand, whereas Churchill thought a grand alliance of European powers, including the Soviet Union, would deter German aggression, Chamberlain persisted in believing alliances would lead to war and instead pursued bilateral negotiations with Hitler on the basis of self-determination for the German-speaking minority in Czechoslovakia. Chamberlain’s decisions not to seek Soviet support against Germany or to fight over Czechoslovakia are placed in the context of advice from the Foreign Office and the chiefs of the armed forces. Churchill’s opposition to surrender to Hitler’s threats is explained in terms of the effect the fall of Czechoslovakia would have on the balance of power and also of his reduced fear of air attack following reports of the effects of bombing in the Spanish Civil War. Reactions to the Munich settlement show that both Chamberlain and Churchill’s positions had considerable public support.

A review of the literature on appeasement shows how historians have been unable to reach a consensus even when using much the same sources. Revisionists have challenged Churchill’s account of the 1930s, but anti-revisionists have tended to be even more critical of Chamberlain than Churchill was. Reasons why historians differ include ambiguity in the use of the term ‘appeasement’; lack of clarity about the other half of Chamberlain’s policy, deterrence; uncertainty about counterfactuals; reproduction of rival departmental viewpoints preserved in the archives; and differing perspectives of historians reflecting influences during their training.

The challenges facing Chamberlain on becoming prime minister are put in a world context by examining Anglo-American and Anglo-Japanese relations, and contacts between President Roosevelt and Chamberlain. The focus then turns to Europe and Chamberlain’s double policy of appeasement and rearmament. The prime minister’s by-passing of the Foreign Office in his attempts to establish better relations with Italy and Germany, which eventually led to the resignation of the foreign secretary, Anthony Eden, is criticised. However, Churchill was hardly less optimistic than Chamberlain about what diplomacy might achieve. Belief that détente with Germany was possible implied long-term deterrence with expansion of the armed forces restricted to what would not destabilise the economy. A defence review led to a decision that the army should be prepared to fight in support of European allies only after the United Kingdom, its trade routes, and overseas territories and interests had been made secure. This decision, which was in line with Chamberlain’s ideas, has been much criticised by historians, but Churchill also gave priority to air defence and agreed that for the time being the strength of France’s defences meant the army was not a prime factor in Britain’s safety.

Historians of appeasement make different assumptions about Britain’s ability to influence events through the threat or use of military force or economic sanctions. Attempts at measuring power are examined critically and key factors identified, including the armed forces, the arms industry, the wider economy and public willingness to support foreign policy. The strength of the Royal Navy is discussed in relation to the size of other navies and to Britain’s commitments, and Churchill’s comment that the Chamberlain government did not neglect the navy is noted. In contrast, Churchill described the loss of Britain’s lead over Germany in air power as a disaster. Britain and Germany’s air power are compared in the context of technical developments. Britain’s limited capability to support France on land is explained, with particular reference to tanks, which Churchill had pioneered. Historians’ debates about the adequacy of Britain’s arms industry are discussed in relation to problems encountered by Germany in rearmament. It is argued that the principal reason why Britain lagged behind Germany was Chamberlain’s unwillingness to accept Churchill’s advice to divert industry from civil trade and industry to producing munitions. The possibilities of collective security through the League of Nations or Churchill’s concept of a grand alliance are explored and the importance of intelligence in influencing perceptions of power emphasized.

From late 1934 Churchill and Chamberlain were influenced by intelligence reports on the scale of German rearmament. Churchill successfully pressed the government to accelerate the expansion of the RAF. Chamberlain agreed in principle to a defence loan, thereby making possible much higher defence expenditure than when he had insisted on balanced budgets. Both men supported appeasement of Mussolini when he attacked Ethiopia, since both saw Italy as a potential counterweight to Germany. Both Chamberlain and Churchill advocated an early end to League of Nations sanctions against Italy after the collapse of Ethiopian resistance. The connection between the Ethiopian crisis and the German military occupation of the Rhineland in March 1936 is explained, Hitler having been encouraged by the failure of sanctions, the consequent reduction in British prestige and the breach between Italy and the western powers. Churchill denounced the British rearmament programme, announced in the same month, as inadequate, and urged a greater diversion of industry to defence contracts than Chamberlain thought safe. On the other hand, both men gave priority to the air force and opposed a commitment to send the army to France.

Some historians have seen continuity between appeasement and Chamberlain’s passive strategy in the Phoney War, but the evidence presented here is that he was not anxious to make peace. Churchill and Chamberlain initially agreed it was best to stand on the defensive while blockade weakened Germany, but their views diverged as Churchill looked for ways to take the offensive against Germany. Churchill was largely responsible for the Allied defeat in Norway but it was Chamberlain who paid the political price, his resignation being a necessary step to persuade the Labour Party to agree to enter a national government. However, Chamberlain loyally served Churchill when the latter became prime minister. In particular, Chamberlain supported Churchill’s policy of fighting on even when France looked for a way out of the war. The forces that the Chamberlain government had created, although deficient in a number of respects, stood the test of war reasonably well. However, pre-war concerns about the necessity of American economic support and British strategic overstretch proved to be well founded, as was demonstrated by the collapse of British power in the Far East. Moreover, even in victory Britain was unable to exercise effective influence in Central Europe.

Starting with the academic debate about whether Chamberlain believed or merely hoped that he had secured peace at Munich, the main theme is the prime minister’s attempts to balance détente and deterrence. Policy was based on the prime minister’s persistent hope that Hitler shared his desire for peaceful change in Europe. Even so, defence expenditure rose rapidly. Initially Chamberlain’s focus was on air power, but from February 1939 he reluctantly accepted that France must be supported by land forces. Churchill was if anything even slower to see the need for an expeditionary force, but welcomed steps to turn Britain into a military power. Germany was known to be experiencing economic strain as a result of rearmament, but whereas Chamberlain thought that made peace more likely, Churchill saw it would be more in keeping with Hitler’s character to make a move before he faced a domestic crisis and before British rearmament was complete. Even on the eve of Hitler’s seizure of the rump of Czechoslovakia Chamberlain was predicting Europe would settle down for a period of tranquillity. However, when his hopes were disappointed, he promised a review of every aspect of national life relating to defence, including the questions of a ministry of supply – long advocated by Churchill – and conscription.

There are few more contrasting historical reputations than those of Winston Churchill and Neville Chamberlain. On the one hand, there is the hero who led Britain in its finest hour when it stood alone against Nazi Germany in 1940. On the other, there is the man of Munich who attempted to appease Hitler by agreeing to his territorial demands on Czechoslovakia in 1938. Appeasement subsequently became a byword for weakness and shameful failure to stand up to dictators. Even today diplomatic compromise with an authoritarian regime is frequently criticised as another Munich.

A counterfactual of what might have happened if Churchill rather than Chamberlain had become chancellor and then prime minister is used to compare the two men. The evidence suggests foreign policy would have differed little before 1938. Like Chamberlain, Churchill would have prioritised the German threat over the Japanese, and would have tried to gain Italian support. Nor would he have used force to reverse Hitler’s occupation of the Rhineland or the Anschluss. On the other hand, Churchill’s approach to Czechoslovakia was fundamentally different from Chamberlain’s, being based on collective security rather than bilateral negotiations with Hitler. It is uncertain, however, whether an effective alliance could have been constructed to deter Germany. Churchill would have rearmed more rapidly than Chamberlain, being more willing to take risks with the economy, but both men prioritised the air force over the army, and for technical reasons British air power was not formidable in 1938. The question of whether it would have been better nevertheless to fight in 1938 rather than 1939 cannot be answered with certainty. Chamberlain’s personal diplomacy undoubtedly had serious shortcomings, but there is room for disagreement on moral issues associated with the Churchillian alternative, including the sacrifice of Ethiopia; the use of war as an instrument of foreign policy, particularly when public opinion was not united; and the risk of allowing Stalin to decide whether there should be peace or war.

Chamberlain’s first challenge on becoming chancellor in 1931 was how to deal with the Great Depression. The reasons why his policies on trade and war debts placed strains on Anglo-American relations, and the consequences for Britain’s ability to wage war in future, are explained, as are the reasons why Churchill agreed with his actions. The responses of the two men to the deterioration in international relations, beginning with the Manchurian crisis and the breakdown of the Geneva Disarmament Conference are compared. There then follows an analysis of how defence policy was transformed in 1934 by Chamberlain working within government for priority for the RAF and by Churchill pressing in the House of Commons for parity with Germany in the air. Priority for air defence implied delay in preparing the army to fight in Europe at the outbreak of war. Chamberlain was also successful in ensuring that Germany rather than Japan was recognised as the main threat, but he failed to persuade Cabinet colleagues that Britain should seek a non-aggression pact with Japan, the chief obstacle being the adverse effect such a pact might have on Anglo-American relations.

Chamberlain and Churchill’s characters and attitudes to war are compared as a partial explanation of their different reactions to events in the 1930s. The two men are placed in the context of how foreign and defence policy was formed, and the principal people with whom they interacted in Whitehall are introduced. Particular attention is paid to the limitations of the intelligence services and to Churchill’s contacts and sources of information, including membership of an official committee on air defence.