Complex sentence: By age 20, Mannock had joined the Labour Party and whilst he burned with a sense of social injustice, according to Jim Eyles, with whom Mannock stayed in Wellingborough, Mannock was deeply patriotic and a fervent supporter of the British Empire.
Split into simpler sentences: By age 20, Mannock had joined the Labour Party and whilst he burned with a sense of social injustice. According to Jim Eyles, with whom Mannock stayed in Wellingborough, Mannock was deeply patriotic and a fervent supporter of the British Empire.