The turbulent relationship between Elizabeth I and Mary, Queen of Scots dominated English and Scottish politics for 20 years, and in February 1587, in the face of unrelenting pressure from parliament and her councillors, Elizabeth signed her cousin's death warrant. Mary was executed a week later, her head severed in three blows. Here, John Guy, the author of the 2004 biography upon which 2019 film Mary Queen of Scots is based, takes us behind the scenes and argues that Mary was as much the victim of the pen as of the executioner's axe.