The King was urged to send Adolf Hitler birthday greetings in the hope of staving off the Second World War, secret papers reveal.
British-German relations were already at breaking point when the Nazi dictator turned 50 on April 20, 1939.
He celebrated with a 50-limo motorcade and a parade of 50,000 troops.
British officials and politicians feared that if King George VI ignored the occasion, Hitler would be insulted. But they also worried about exposing the monarch to criticism for appearing to cosy up to the evil regime in Berlin.
Now declassified Government documents have shown how the question was the subject of urgent debate at a Cabinet meeting on April 19.
Prime Minister Neville Chamberlain was desperate to avoid another war with Germany, even though the Nazis had breached the Munich Agreement by annexing Czechoslovakia.
Foreign Secretary Lord Halifax pointed out that it was “normal practice” for the King to send birthday messages to foreign heads of state.
Cabinet meeting minutes recorded how Halifax warned that Hitler might see any refusal to acknowledge his 50th as a “personal affront”.
In the end a compromise was reached in which the King sent a message of congratulation rather than the traditional wishes of good health. But war broke out anyway in September.
