Leak of Hitler's Operation Green directive to Britain

The leak of Adolf Hitler’s Operation Green directive to Britain converts the approaching crisis from a contest of threats into a question of concrete military intent. A five-page German document, delivered without explanation to Hugh Legat’s home, sets out how Germany would attack Czechoslovakia. Its arrival does not identify the source or settle every question of authenticity, but its operational detail gives the British government evidence of what Hitler’s ultimatum could mean in practice.

The document reaches Legat

Legat was at home when a small car stopped outside. He heard a clatter downstairs, then saw a figure in a hat and dark coat move away from the house and get back into the vehicle. He reached the front door too late to catch the car, which was already turning into Great Peter Street. On the doormat lay an official-looking envelope addressed to him, though his surname had been misspelt as Leggatt. There was no accompanying message to explain who had delivered it or why it had been sent to him.

The envelope contained a document headed Berlin, 30 May 1938, marked with the reference OKW No. 42/38 and a classification indicating strict military secrecy. Legat did not linger at home to investigate its origin. Within ten minutes he was on his way back to the office, carrying the papers as London displayed other signs of strain: motorists queued for fuel, a peace vigil was under way at Westminster Abbey, and newsreel cameras glared against the dark walls of Downing Street. The juxtaposition makes the document’s passage into official hands part of a city already bracing for crisis, rather than an isolated act of espionage.

Cadogan examines the evidence

At the Foreign Office, Legat took the five typewritten pages to Sir Alexander Cadogan. Cadogan was irritated at being disturbed, but the first line, the final signature of Adolf Hitler, and the certification by a German General Staff officer immediately changed his manner: he sat bolt upright. The directive described a war on two fronts with the main effort in the south-east, under the strategic concentration called Green. The formal language and military markings lent the document the appearance of an official order, though appearance alone could not prove its authenticity.

Cadogan read the pages closely, turning each one over and placing it neatly to his right before moving to the next. His command of German mattered to the assessment: he had been in charge of the British embassy in Vienna in the summer of 1914, when Archduke Franz Ferdinand was assassinated. The directive instructed German forces to create, within the first two or three days, a situation that would convince potential intervening states that Czechoslovakia’s military position was hopeless. Rapidly deployable army formations were to break through the frontier fortifications and push into the country, while the bulk of the mobile army followed at speed. The Luftwaffe was assigned a surprise attack, with aircraft crossing the frontier at the same time as the first army units.

The plan’s value lay in the specificity of its sequence and methods. It did not merely predict a German advance: it described the intended effort to overwhelm Czechoslovak resistance quickly and discourage outside intervention. The simultaneity of air and ground operations, and the emphasis on creating an early impression of military hopelessness, made the directive a picture of how the invasion was meant to work, not simply a statement of hostile intent.

What the leak establishes—and leaves unknown

After finishing the document, Cadogan squared the pages and called it extraordinary. He agreed with Legat that it appeared genuine, while treating that conclusion as an assumption on which to proceed rather than as certainty beyond question. The date, 30 May, placed the order months before the immediate crisis. Cadogan also recognized that its declaration of an unalterable decision to smash Czechoslovakia by military action echoed Hitler’s words to Sir Horace Wilson that morning. The document therefore joined an earlier written plan to the threats being made in the present.

The leak nevertheless left the essential question of provenance unanswered. Cadogan asked who had supplied the document, why it had been supplied, and, above all, why it had been delivered to Legat. Legat said he could answer none of these questions and felt compromised simply by possessing it. Cadogan knew that opponents of Hitler had made contact with Britain over the summer, offering to overthrow the regime if Britain stood firm over Czechoslovakia. He described them as an incoherent collection of disaffected diplomats and aristocrats who wanted to restore the monarchy. This was the first specific material they had received from such opposition, but Cadogan cautioned that it added little to the basic knowledge that Hitler wanted to destroy Czechoslovakia quickly. The sender’s identity and intention remain unresolved in the scene; the document’s significance rests instead on the military detail it makes available.

The warning within the wider crisis

The directive reaches British officials as the diplomatic timetable is collapsing. Neville Chamberlain tells the Chiefs of Staff that Hitler has rejected waiting even a week and intends to invade on Saturday. Chamberlain reports that he had hoped for an orderly transfer of the Sudeten territory, subject to a plebiscite, and that Wilson had warned Hitler that Britain would support France if France fulfilled its treaty obligations to Czechoslovakia. The leaked order gives this immediate threat a strategic counterpart: it indicates a prepared assault designed to defeat the Czechs quickly and make intervention seem futile.

The British response to the danger remains contested. In the Chiefs of Staff discussion, Chamberlain worries that partial mobilization could either show Hitler Britain is prepared to fight or push him into war. The directive sharpens the stakes of that choice without resolving the dilemma. It is evidence of an intended attack, but it does not itself determine how Britain should answer. Later, as a telephone message from Berlin reports that Hitler has agreed to postpone mobilization for twenty-four hours at Benito Mussolini’s request, Sir Horace Wilson recounts Hitler’s insistence that the crisis must be settled by Saturday and his attention to the deadline. The pause changes the immediate clock, not the invasion plan revealed by the leaked papers.

The episode’s force comes from the contrast between the anonymity of the delivery and the precision of what it carries. A misspelt name on an envelope leads to a plan bearing Hitler’s signature; an unexplained act brings into the Foreign Office a carefully structured account of how Czechoslovakia is to be broken. The leak cannot disclose who risked passing the document or what result they hoped for. It does, however, make the threat harder to treat as mere diplomatic theatre: behind the deadline and the public bargaining stands an operational scheme for invasion.