Complex sentence: Previously he was the Director of Centre for the Study of Terrorism and Political Violence at the University of St Andrews, Scotland, and he was largely responsible for the worldwide media exposure the Centre received as he was a consultant to CNN on terrorism.
Split into simpler sentences: Previously he was the director of the Centre for the Study of Terrorism and Political Violence at the University of St Andrews, Scotland. He was largely responsible for the worldwide media exposure the Centre received as he was a consultant to CNN on terrorism.