Allen completed his doctoral studies in Theology (Islamic Studies) at the University of Birmingham where he was funded by the (AHRC - Arts & Humanities Research Council) to explore the discourse and theory of Islamophobia. At the same time, he also taught in Birmingham's Sociology department on its 'Multiculturalism', 'Media, Culture & Society' and 'Research Skills & Methods' imodules.

Allen returned in 2008 to Birmingham, where he is a Research Fellow post in the Institute of Applied Social Studies (IASS) in the School of Social Policy. He was previously Director of Research & Policy at BRAP (formerly Birmingham Race Action Partnership), a Birmingham-based equalities and human rights agency www.brap.org.uk. Before that, Allen was Visiting Lecturer at the University of Wolverhampton, Associate Lecturer at the Open University and Research Fellow at the Markfield Institute of Higher Education, 'Muslims in Britain'.

He has published and presented his research widely both in the UK and across Europe and has recently been commissioned to edit a series entitled, 'Muslim Diversities' with Routledge.

In the past, he has worked with a number of Muslim and non-Muslim organisations and institutions and through this has secured a number of research grants. As part of this, he has undertaken research that has been commissioned on behalf of, or submitted to, the House of Lords Select Committee on Religious Offences, the British Council and the Higher Education Academy's Subject Centre for Philosophical and Religious Studies amongst others. More recently he has worked on projects for the European Commission on Security Issues in Europe, the Greater London Authority (GLA), the London Borough of Hounslow and Football Unites Racism Divides.

He has in the past undertaken work for the media including Channel 4, the BBC (through various organisations), Central (ITV), Islam Channel, Press TV and Sky News. He co-presented with Musab Bora a topical weekly radio show on Birmingham based radio station, Unity FM and more recently, presented a talk-based equalities and news programmeon South Birmingham Community Radio.