At a time when women had few freedoms, she was a cornerstone of high society and behind-the-scenes political dynamo. However it was Jennie's love life that marked her out, causing scandal and earning her the epithet 'more panther than woman'.

Yet, in many ways, Jennie was deeply loyal to her husband. When he was dying of syphilis she took him on a round-the-world trip to conceal his violence and mania. He returned in a straitjacket with only weeks to live. After Randolph's death her great project became her son, Winston...