Complex sentence: Hardy began his activity as a revolutionary militant during the Second World War when he joined a tiny Trotskyist group, the Union Communiste, led by Barta (David Korner) a Romanian Trotskyist.
Split into simpler sentences: Hardy began his activity as a militant during the Second World War. The Independent, John Lichfield, 18 September, 2010 He then joined a tiny Trotskyist group, the Union Communiste, led by Barta (David Korner) a Romanian Trotskyist.