Allen was awarded his doctorate by the University of Birmingham in 2006. He also holds a bachelors degree from the University of Wolverhampton. He began his academic career by teaching in the University of Birmingham's Sociology department. In 2006, Allen left the University to take up the post of Director of Research & Policy at BRAP (formerly Birmingham Race Action Partnership), a Birmingham-based equalities and human rights agency. During his time at BRAP, he oversaw a number of projects that explored issues of inequality and discrimination. At the same time, he held a Visiting Lecturer post at the University of Wolverhampton, an Associate Lectureship at the Open University and Research Fellow status at the Markfield Institute of Higher Education. He returned to the University of Birmingham in June 2008 as a Research Fellow in IASS.