Andrew Marr looks into the life of Scotland's most bothersome poet, Hugh MacDiarmid. MacDiarmid reinvented Scots as a language for serious writing, at various times called for a Scottish fascism, tried to create an independent Scottish communist utopia, and was under surveillance by MI5 for many years. During his life he was involved in plots to capture Edinburgh Castle and steal the Stone of Destiny, but he also found time for a literary life in which he would write the most powerful poetry in Scots since the days of Robert Burns and to start a Scottish renaissance that goes on to this day.