Matthew's research examines the role of secret intelligence in diplomacy and grand strategy, and focuses in particular on intelligence in the failure of Anglo-French relations in the Second World War and early Cold War. Additional research interests include clandestine diplomacy, intelligence cooperation and rivalry, and identity and personal relations in historical inquiry. He is published in Intelligence and National Security. He is a Fellow of the Sir Michael Howard Centre for the History of War, a Research and Communications Officer at the Ramphal Institute, and a Rotary International Global Grant Scholar (Peace and Conflict). He is also a Visiting Research Scholar at the Centre de Recherches Internationales (CERI), Sciences Po.