Why did Chamberlain remain Prime Minister of Britain until 10 May, 1940?

English lad here. Some people won't like the actual reason why Chamberlain remained Prime Minister. But here it is: The British - certainly the English - people didn't actually have a problem with the National Socialists. It's only when they started on us that we came to hate them.

You need to realise that we were a 100% White, and strongly-Nationalist nation back then.

Chamberlain was certainly wrong in his appeas*m*nt policies. And no, he wasn't buying time with it. It is clear from his statements from the period that he believed that it was possible to stop Hitler with diplomatic concessions. In this, he was certainly in accordance to the general public sentiment, which was, as other answers and comments point, against war. Certainly, Britain was rearming during the period, but the point of Chamberlain's politics was to avoid war, not to postpone it to a time when Britain was better equipped.

It is important to remember the course of German demands and acquisitions in the 1930's, to understand that those demands were not unreasonable or demented. Germany reannexed the Saar in 1935, through a plebiscite that was provisioned by the Versailles Treaty. It was a region with a majority of German population. Then Germany remilitarised the Rhineland, which was, and never ceased to be, metropolitan German territory. That put an end to a buffer zone between Germany and France, but it can hardly be called an absurd.

Then Germany demanded four other things: 1. the Anschluss of Austria (which had an overwhelmingly German population, that gave strong popular support for the idea), and the annexation of 2. the Sudettenland, 3. Memel, and 4. Dantzig/Gdansk. All those regions were German-majority regions; so, as an abstraction, such demands did not offend the sence of justice of most people. The fact that these apparently reasonable demands were part of a German strategy for war and domination of Europe was not immediately apparent - and was in fact the kernel of the debate about appeas*m*nt.

Those who thought that the demands were reasonable and fair, and that Hitler, albeit being a tyrant, was a tyrant of the old kind, with limited strategic goals that could be negotiated, favoured appeas*m*nt: to give Germany its reasonable demands, with reasonable assurances for reasonable protections of the rights of the ethnic minorities in those regions. The fate of political oppositionists in Memel, Gdansk, the Suddeten, or Austria, was of minimal concern - after all, those people were in great part already subjected to brutal dictatorial regimes, like those of Dolfuss/Schuschnnig, Bock/Pilsudsky, or Smetona, and that was considered pretty normal.

Those who thought that the German demands, reasonable as they were, were just a part of an expansionist strategy, which could be much more ambitious than the mere political reunification of German ethnicity, opposed appeas*m*nt, and proposed stronger diplomacy - of which, of course, threats of war were an integral part. Those people were not visionaries - Hitler himself had extensively written about his strategy, and made no secret of the fate he intended to impose into the Slavic or otherwise non-German populations of Eastern Europe.

And so, the Sudetten crisis was to be the watershed moment that finally cleared which of those political currents was correct. Austrians were for the most part happy to be anschlussed - and those who weren't, either were, like Communists and Socialdemocrats, already being repressed under Austria's own national government, or, like Schuschnigg's loyalists, didn't attract much sympathy, as they were the ones doing such repression. Czechoslovakia was different - it was a democracy, and its inhabitants weren't German or happy with German domination. Hitler promised to annex the Sudetten but to otherwise respect Czechoslovakia's independence. He broke that promise and invaded and subjected the Czech part of Czechoslovakia, showing in practice that he wouldn't be stopped by diplomacy and that his politics wasn't merely a politics of unifying ethnic Germans.

Now, Czechoslovakia had a quite formidable defensive line in the Suddeten. While they obviously could not counter-attack and invade Germany, they could have set up fierce resistance, much more than Poland did. The terrain is difficult, not the plains and prairies of Poland, and Czechoslovakian fortifications were strong and modern. This point shows, I think, the extent of Chamberlain's mistakes. If he was intent to rearm Britain for a future war, then he shouldn't allow the Germans to remove the Czechoslovakian defensive line, leaving the poor republic defenceless when the following, predictable, onslaught came. He was really deluded about Hitler's intentions and strategies.

Only then public opinion turned against appeas*m*nt. That would be the precise moment when Chamberlain could have been ousted. But Chamberlain himself recognised that we was wrong, and changed his mind on the possibility of containing Hitler through diplomacy. He was weakened by the blunder, and Churchill, who had opposed the policy, was strengthened. But it didn't cost Chamberlain his leadership within the Tories, and he remained prime minister. The moment of his possible fall had passed. When the invasion of Poland came, Chamberlain was no longer defending a policy of appeas*m*nt - and indeed his government immeadiately declared war on Germany, as it had promised before. And so, there was no particular reason why Chamberlain would be ousted in September 1939. He survived the crisis of March, when Hitler occupied "Bohemia and Moravia"; he was not to survive the crisis of the failure to defend Norway. But there was no particular British internal crisis due to the invasion of Poland.

What ensued was the drôle de guerre - the inaction of the allies in the Western Front, while the Wehrmacht slaughtered Poland. This was another wrong policy, but it cannot be blamed upon Chamberlain alone; any action would have to be started from French territory, and the French government, not Chamberlain, was the main culprit of the drôle de guerre.

His fall came with the invasion of Denmark and Norway, not because the British public opinion realised that war was unavoidable, but because it realised the war was iminent, and that the invasion of France, and probably Belgium and the Netherlands, was a matter of days. Thence Chamberlain lost his position, not directly as a punishment for appeas*m*nt or drôle de guerre, but because it was consensual that all main parties should be included in government, and Churchill was by far more acceptable to Labour (and Liberals, though that probably didn't matter as much).

Luckacs' two books on the subject (The Duel: 10 May–31 July 1940: the Eighty-Day Struggle between Churchill and Hitler and Five Days in London, May 1940) are a good read, mapping quite well the positions of Churchil and Chamberlain (and Labour's. And Halifax's - whose dellusions seem to have been more persistent than Chamberlain's) during the crisis that lead to the fall of France.

From a German perspective I also think it is unfair to paint Chamberlain as a pacifist who would avoid war at all costs and was unsuitable for the job. He declared war together with France on September 3th, two days after the invasion.

If people are unhappy with the "Phony War", I would like to ask what exactly do they imagine what England and France could have done.

The border between France and Germany was heavily fortified. So Germany has a very good defendable and prepared choke point with a fully equipped modern army. For people who did not experience war it should be pointed out that most people remembered one of the worst wars 20 years earlier who killed many of their family and friends in the horror of trench warfare and were therefore for a good reason not eager to another war.

Moving heavy mobile units or massive infantry was considered impossible in the Ardennes. (which was the reason that Germany's attack was so successful).

Moving through Belgium or the Netherlands to attack Germany would violate their neutrality as long as both countries do not agree. This would in return paint a big red target on their chest which a neighbor who defeated the stronger Poland in weeks. Using force would not only make the Allies the aggressor, it would make the "The Rape of Belgium" propaganda of the Allies in WWI ridiculous.

The Soviet Union also invaded Poland and shared it with Germany. So the obvious partnership excluded a very advantageous two front war and it also allowed Germany to be supplied with goods. Blockading the North Sea is much now less effective.

All points on the western front were also valid for Germany, as France had also strong fortifications and invading the Low Lands again would offer opportunities for France and England to countermoves. So I do not think replacing Chamberlain with Churchill would have any immediate effect and therefore Chamberlain could not be blamed for the inactivity.

While the other answers give a lot of historical insight, I feel the answer to the question why Churchill didn't become prime minister earlier is because there was no majority in the British Parliament who preferred another parliamentarian over Chamberlain as PM.

This may seem like an answer that is trying to be technically clever rather than insightful, but as it stands the question is mostly illustrating a confusion about how the British political system works. Once this technical answer is given, one may of course ask a follow up question along the lines of "why was there no majority in the house of commons to topple Chamberlain before May 1940"? Which in turn may be related to public support as explained in the other answers.

But the answer to the original question (as stated) falls squarely into the technicalities of how the British Parliamentary system works: even if a PM is exceedingly unpopular (which Chamberlain was not, as elaborated in the other answers) that does not at all mean that s/he will cease being PM.

Some context to support Semaphore's answer... drawing (partially) from John Terraine's "Right of the Line".

The policy of appeas*m*nt is sometimes used to portray Chamberlain as a pacifist under whom Britain was hopelessly unprepared for war. Yet when he was Chancellor of the Exchequer (in charge of finances) in 1935, he rejected an expansion plan prepared by the RAF (one of several) ... but on the grounds that it was far too small!. Which is unusual for a guardian of the public purse. So he definitely saw dangers ahead and wanted to prepare for them - even against popular opinion.

And an opinion : Appeas*m*nt was quite a cunning strategy and accomplished its goals. Only one of these was to buy time for rearmament. At the time of Munich (Spring 1938) Britain had only a few Hurricane fighters, whose guns froze above 15000 feet, and less than one squadron of Spitfires ... and a lot of biplanes like Gloster Gladiators (*). Even with Germany's relatively poor preparedness at the time, it would have been an unequal match.

Another goal was to give Hitler a real choice ... abide by the agreement, or break it.

But the main goal was to place the responsibility clearly and absolutely on Hitler if he did break it, and engineer the moral outrage that would unite opinion behind going to war. You will notice that it was "this piece of paper" and not Neville Chamberlain, that promised "Peace in our time".

Without that - say, if Churchill had been PM in 1938 and declared war - perhaps even in 1939 as Chamberlain did - he would have been regarded as a rash warmonger (as he was in the 30s) and the war effort much weakened and dis-united by dissent and bickering. Just as we can still see even 15 years after the 2003 war against Iraq, where the basis for war (the WMDs) was less strongly established.

Appeas*m*nt firmly established in the minds of the British that, in 1939, regrettably, the job had to be done and we'd better get on with it.

That being the case, Chamberlain had been proved right in his preparations, and was the logical choice to run the job, at least until the failures e.g. in Norway became apparent.

I can't find the quote attributed to Churchill around that time, that hints he fully understood all this. It was along the lines of "Poor Mr. Chamberlain will be badly treated by the history books. I know this, for I will write them". And of course, he did.
EDIT to update : the actual quote (source) doesn't explicitly support this.

For my part, I consider that it will be found much better by all parties to leave the past to history, especially as I propose to write that history myself.

(*) For an idea how well that might have gone down, I recommend a short story "A Piece of Cake" apparently based on practical experience by Roald Dahl. Yes, that Roald Dahl.

those old Gladiators aren't made of stressed steel like a Hurricane or a Spit. They have taut canvas wings, covered with magnificently inflammable dope, and underneath there are hundreds of small thin sticks, the kind you put under the logs for kindling, only these are drier and thinner. If a clever man said, "I am going to build a big thing that will burn better and quicker than anything else in the world,' and if he applied himself diligently to his task, he would probably finish up by building something very like a Gladiator.
I sat still waiting.
Then suddenly the reply, beautiful in its briefness, but at the same time explaining everything. "Your--parachute--turn--the buckle.'

Didn't the British people recognize how ill-suited Chamberlain would be because of his former appeas*m*nt?

No, because it's not true at all. Chamberlain may certainly be an inadequate war leader, but Appeas*m*nt is no evidence for it. If you are suggesting that people might think his earlier Appeas*m*nt meant Chamberlain wouldn't fight Germany, there's little evidence contemporaries believed it, probably because it would have seem blatantly false. Lest we forget, it was under Chamberlain that Britain declared war on Germany.

I realise this goes against the orthodox view first set in 1940 by the highly problematic, scapegoating book Guilty Men, however Chamberlain was not nearly as naively pacifistic as he is often portrayed as. In fact, under his ministry Britain rearmed as quickly as financial and public pressures would permit - and the rest of the British government would have known this.

Chamberlain, his senior ministers, and their advisers had no intention of relying solely on diplomatic means . . . [the British government] embarked on a program of strengthening the armed forces beginning in 1934 . . . Chamberlain observed [that] 'I believe the double policy of rearmament and better relations with Germany and Italy will carry us safely though the danger period, if only the Foreign Office will play up.'

But difficulty for Chamberlain not only resided with the Foreign office that . . . advocated the balance of power. On the left, the opposition Labour Party, supported by pacifist organizations like the Women's international League of Peace and Freedom, argued against rearmament.

_{Maurer, John H., ed. Churchill and the Strategic Dilemmas Before the World Wars: Essays in Honor of Michael I. Handel. Routledge, 2014.}

The key point here is that Chamberlain's rearmament was opposed by the Labour Party. So even if people were to argue Chamberlain was too much of a pacifist to be a war leader, such an attack would have needed to come from within his own party, not the political opposition. As we shall see, he retained the support of the Conservative Party right to the very end.

That's not to say some individuals may have suspected Chamberlain of cowardice or inaction, especially as the phony war drew on, but it would have been an incredible claim shortly after the Chamberlain ministry declared war in 1939. In any case, up to his resignation but there was no general feeling that Chamberlain couldn't be trusted to fight.

Of course, whether he could fight well is another question entirely.

Why didn't Chamberlain resign much earlier, since his championing of appeas*m*nt had clearly failed?

The premise here seems to be that people would have wanted to punish Chamberlain, so to speak, with removal from office for pursuing Appeas*m*nt. The thing is, that is an anachronistic view of the road to war, one certainly not shared by Chamberlain or his contemporaries. The reason is simple: most of them advocated or applauded appeas*m*nt just a year ago.

Chamberlain didn't invent or "champion" Appeas*m*nt, he simply believed he had no other realistic option. Historians now realise that British leaders including Chamberlain were acutely aware of just how weak the British military was, how adverse the strategic situation was, and how constrained they were by the poor economic and financial resources available. The British public at home was still in no mood for war - Chamberlain was universally cheered in the press when he returned from Munich. Overseas, the Dominions refused to support a "war of aggression" against Germany, and the United States remained stuck in its isolationist ways.

[A]ppeas*m*nt enjoyed considerable public support, certainly until the autumn of 1938 . . . [T]he 1967 Public Records Act facilitated greater access to official sources. This allowed historians to compile more detailed analyses, suggesting that the harsh economic, military and strategic realities of the 1930s demanded a policy of appeas*m*nt, Historians highlighted Britain's relative military weakness, noting how contemporary politicians were acutely aware of Britain's shortcomings. Furthermore, attention was drawn to . . . Japanese expansionism in the Far East, the financial constraints on rearmament, [and] the pro-appeas*m*nt Dominions.

_{Hucker, Daniel. Public Opinion and the End of Appeas*m*nt in Britain and France. Routledge, 2016.}

This doesn't mean Appeas*m*nt was necessarily the right move. Perhaps an early response to Hitler could have intimidated him into backing down. Or perhaps not: threatening military response would have been hollow. This remains an area of scholarly debate. The point, though, is that Chamberlain acted according to the public will, pursuing a strategy that seemed reasonable to many of his contemporaries.

It's important to note that appeas*m*nt was over by early 1939, long before the war had broken out. Chamberlain was not appeasing Hitler for the sake of appeasing Hitler, but rather trying to do his best given the hand he was dealt, and he changed his approach as the situation changed in the lead up to war. By 1939, Appeas*m*nt had "failed", but it also "succeeded". Its failure to contain Germany helped steeled public opinion in both Britain and her Empire for the upcoming war. Moreover, delaying the confrontation bought Britain precious time to rearm, which laid the foundations for victory in the Battle of Britain.

Thus, it wouldn't have made much sense for people to replace him for the association with appeas*m*nt after the war begun.

1940 May 10 is exactly the same date as the German invasion of Benelux and France . . . In other words, the end of the Phony War apparently has something to do with this, but it's hard to see which is the chicken and which is the egg.

Chamberlain retained the support of his party, and therefore by extension Parliament, up until his resignation. His position only really crumbled during the Norway Debate in the aftermath of the failed expedition, on 7 and 8 May. Most notably, retired Admiral of the Fleet Lord Roger Keyes delivered a scathing speech, and many others criticised the Chamberlain ministry's lack of preparations as well as general handling of the campaign.

However, none other than Churchill closed the debates with a strong defence of the government, and Chamberlain ultimately still won the vote of confidence by a majority of 281 to 200.

Nonetheless, at this point Chamberlain believed that a national unity government was necessary for the war effort. Since the Labour and Liberals wouldn't serve under him, he was obliged to resign. The first choice to succeed him was actually Foreign Secretary Lord Halifax, not Churchill. In the end however Halifax declined to step up to the position, so it ultimately went to Churchill.

The meetings to arrange for the government restructuring took up the day, so that the handover went into effect on Friday, 10 May. It was thus a total coincidence that on the exact same day Germany launched its offensive.