In February 1941, a group of Americans arrived at Bletchley Park, in what marked the beginnings of an extraordinary UK-USA intelligence alliance that continues to this day. To commemorate the 80th anniversary of this alliance, we've produced an exciting four-part documentary series exploring how this alliance began, and what led to it's remarkable success, with insights from historians and experts on both sides of the Atlantic. Episode one follows Bletchley Park’s Research Historian, Dr David Kenyon and the National Security Agency’s senior historian, David Hatch, as they explore the tentative first steps taken by the UK and USA in February 1941 to begin sharing their codebreaking secrets. Kenyon and Hatch explore how this relationship developed during 1941 in the months before America formally entered World War Two.