The Original, Official War Office Order Notifying British Commanders and Troops Worldwide that Italy Has Declared War on the Allied Powers: Created on June 10, 1940, the day Mussolini joined the Nazi war effort

In America, President Roosevelt broadcast on the radio the promise of support for Britain and France with “the material resources of this nation.”

In 1935 Hitler violated the Treaty of Versailles by introducing military conscription and building an air force. The following year German troops occupied the Rhineland, also a treaty violation. in 1938, Germany invaded Austria and incorporated it into the Reich. The German military was then mobilized, and was emboldened by the lack of opposition in France and Britain, which were lost in a dream of peace, pacifism, and disarmament. Their policy was to appease the Germans. On September 30, the appeasement policy reached its height, when at the notorious Munich Conference, British Prime Minister Chamberlain and his French counterpart gave in to all of Hitler’s demands to dismember Czechoslovakia. The Germans then occupied the Sudetenland and the Czech government collapsed. In March 1939 the Germans gobbled up the rest of Czechoslovakia, in blatant violation of the Munich accord.

At this point Britain and France began to awake and gave a guarantee that they would defend Poland in the event of a German attack. That attack came on September 1, 1939. On September 3, Britain delivered an ultimatum to the Germans, written by the Foreign Secretary Lord Halifax, and delivered to them at 9 am: Unless German forces began to withdraw from Poland by 11 am, Britain promised to fulfill its obligations to Poland along with the French. The ultimatum rejected, Britain, Australia and New Zealand declared war on Germany on September 3. Similarly the French issued an ultimatum, which was presented in Berlin at 12:30, saying France would be at war unless a 5 pm deadline for the troops’ withdrawal was adhered to. Thus they declared war the same day.

Italy had been unprepared for war when Hitler attacked Poland, and took no action herself. But as the German blitzkrieg rolled over Western Europe, the Italian leader, Benito Mussolini, realized that if Italy was to reap any positive advantages from partnership with Hitler, it seemed that Italy would have to abandon its nonbelligerent stance before the western democracies had been defeated by Germany singlehanded. The collapse of France convinced Mussolini that the time to implement his Pact of Steel with Hitler had come, and on June 10, 1940, Italy declared war against France and Great Britain.

Typed document, initialed from the War Office itself, bearing the “secret cipher telegraph” red stamp that marks it as the original, and marked “secret,” then ""clear,"" dated June 10, 1940, being the official notification to Britain’s global forces, simple and direct in its message: “War has broken out with Italy.” The telegram is addressed to Commonwealth locations ranging from the strategy position at Gibraltar to the Middle East to the Far East to Africa. Among the recipients were governors and commanders-in-chief of the Middle East, China, Malaya, East Africa, Egypt, Sudan, Palestine and Transjordan, Jamaica, Ceylon, and Malta. Copies were to be sent to official parties both domestic and foreign, such as the Army Council and the Director of Mobilization.

The reaction by the Allies to the declaration of war was swift: In London, all Italians who had lived in Britain less than 20 years and who were between the ages of 16 and 70 were immediately interned. In America, President Roosevelt broadcast on the radio the promise of support for Britain and France with “the material resources of this nation.” FDR also said of Italy’s move, “On this tenth day of June 1940, the hand that held the dagger has struck it into the back of his neighbor.”

The Germans entered Paris on June 14, 1940, and were driving still deeper southward along both the western and eastern edges of France. Two days later they were in the Rhône valley. Meanwhile, French General Weygand was still pressing for an armistice, backed by all the principal commanders. Reynaud resigned office on June 16, whereupon a new government was formed by Marshal Philippe Pétain, the revered and aged hero of the Battle of Verdun in World War I. In the night of June 16 the French request for an armistice was transmitted to Hitler. As for Italy, after declaring war, there was an Italian offensive into southern France that stalled at the fortified Alpine Line. On June 24, 1940, France surrendered to Germany. Italy occupied a swath of French territory along the Franco-Italian border. That was her gain.