Deepayan is a Policy Adviser for Oxfam GB's work on the arms trade and its impacts on development. His work is focused on ensuring that the ongoing negotiations on the Arms Trade Treaty adequately reflects the impact of armed violence, corruption, excessive military expenditure, and unaccountability on processes of development. 

Deepayan has a background in International Relations and political science with expertise in human security, conflict and emergencies, disarmament, fragile states, international aid architecture, and human development. 

He has a diverse policy and analytical background, and has worked for NGOs, think tanks, consulting companies, academic institutions, and government agencies.  Deepayan has also published a number of papers and reports on human security, aid effectiveness and fragile states, socio-political and security analysis, security and development, conflict, vulnerability, and non-traditional security threats.