In 2011 Rob Leech released his documentary My Brother The Islamist, in which he reconnects with his step brother Richard Dart after he moved to London, converted to Islam, and fell under the spell of notorious radical preacher Anjem Choudary. In that documentary Dart was primarily focused on trying to convince people to follow him and convert to Islam.
Two years later in 2013 Dart was convicted on terrorism charges and sentenced to six years in prison. Leech subsequently set about producing this second documentary, My Brother the Terrorist, which charts his attempts to try and understand his brothers journey from a middle-class white boy in a sleepy seaside town to a man convicted for plotting terrorism. In 2015 a third documentary was aired, Welcome to the Mosque, in which he explores the world of those who worship at the huge East London Mosque.