Mosques and hotels housing asylum seekers came under attack during the riots that swept across the country earlier this month. The courts have been tough on violent disorder, but File on 4 examines how tackling the possible root causes may require an even stronger effort. Tensions over immigration are still simmering, particularly in areas that have long been in economic decline. Paul Kenyon reports. Producer: Hayley Mortimer Technical Producer: Nicky Edwards Production Coordinator: Tim Fernley Editor: Alys Harte