The decisions made by the British foreign policy makers during the period 18 to 31 March were momentous not merely because they were made on the background of a dramatic shift of the political balance of power in Europe, they were also crucial in so far as, for the first time since the Versailles conference, Britain was forced to consider the undesirability of Germany dominating the whole of Central and South Eastern Europe. Since the result of the major reconsideration was Britain's commitment to defend Poland, which was followed a few days later by a similar commitment to Rumania, it is only too easy to interpret the events of these critical days as leading directly and unequivocally to the assumption by Britain of a new and anti-German stance. While this indeed is the case, and led directly to Britain declaring war on Germany in September 1939, the broader context of the debate that was initiated in March 1939 can easily be overlooked.

Far more importantly, during the last two weeks of March, Britain considered not merely the case of defending either Poland or Rumania but she briefly took into account the need to face Germany with an eastern front, and one to the formation of which Britain was to declare her direct commitment.