Leigh is a Research Officer within ODI’s Global Risks and Resilience programme, and a fellow at The Centre on Armed Groups. His research focuses on armed group dynamics; illicit economies and development; smuggling networks and the intersection with armed conflict; radicalisation; and the security dimensions of climate change.

Currently, Leigh’s work is focused on how communities engage armed actors to advance community self-protection. Leigh's previous work has included research on the smuggling economy and armed networks in northern Niger, and rethinking armed group control to help improve the monitoring of changes in armed group control during civil war. He also led a 12-month project focused on youth radicalisation in the Sahel as part of the pilot phase of a new FAO regional programme supporting youth employment and rural economies in the Sahel. Leigh is part of the Supporting Pastoralism and Agriculture in Recurrent and Protracted Crises (SPARC) programme.

He holds a Masters in Conflict, Security and Development from King’s College London, where he focused his studies on war economies, insurgency and the comparative study of civil wars.