Jack Marrinan was a key moderniser of policing in Ireland. More than anyone, he changed the face of the Garda Síochána, the police force he loved and served.

When younger gardaí were excluded from a pay award in 1961, almost 1,000 members attended a banned protest meeting at the Macushla ballroom in Dublin. Of the 1,000 guards who attended, about 160 were served with disciplinary notices charging them with discreditable conduct. Eleven men, including Marrinan, were dismissed by the commissioner. After being reinstated, Marrinan was offered a promotion but chose instead to represent
rank and file members through what became the Garda Representative Association.

Changing of the Guard tells the story of Marrinan as a transformational figure in the force at a time of great social and economic change. Under his leadership the Garda Representative Association (GRA) evolved into a skilful and powerful negotiating body. Nearly all of the advantages that gardaí enjoy today in their service are built on the foundations he established.