His next work was a biography of 1920s IRA veteran Ernie O'Malley, entitled "Ernie O'Malley, IRA Intellectual" which was published in 1998. Since then, he has written "Armed Struggle - The History of the IRA" (2003). This book, predominantly a history of the modern Provisional IRA, won the politics book of the year award from the Political Studies Association and was shortlisted for the Christopher Ewart-Biggs Memorial Prize. After this, he wrote a broader history of Irish nationalism, "Irish Freedom, The History of Nationalism in Ireland" (2006), which won the Ewart-Biggs Memorial Prize in 2007. He has also co-edited two volumes: "The State: Historical and Political Dimensions" (1999, with Charles Townshend); and "Rethinking British Decline" (1999, with Michael Kenny). He is a frequent media commentator on terrorism and Irish politics and history, including work for the BBC, NPR, the Times Literary Supplement, Newsweek, and the Financial Times. In 2009, he published a study of political violence, titled "Terrorism: How to Respond". In 2016, he contributed to the documentary film "". In 2015 English was elected a Fellow of the Royal Society of Edinburgh.