Moussa leads regionally on social protection, livelihoods, and economic development for the UK Poverty Programme. He is also leading on Oxfam's work in response to the economic downturn, public spending cuts, and their impacts in relation to UK poverty.

He previously worked as a policy adviser for the Equality Challenge Unit, advising higher education institutions on equality and diversity issues, specialising in religion, belief and disability, and as a researcher for the Social Market Foundation think tank, publishing on welfare reform, education and volunteering policy.