Professor Michael J Turner 
Britain and the World in the Twentieth Century [PDF ebook] 
Ever Decreasing Circles

This is a detailed, single volume analysis of Britain“s changing position in the world during the twentieth century. It places British policy making in the appropriate domestic and international contexts, offers an alternative to the more negative, “decline“-obsessed assessments of Britain“s role and influence in global affairs. This book suggests that Britain“s leaders did a better job than some historians think. Michael Turner, in order to understand why they took the options they did, investigates their motives and aims within the international environment within which they operated.