I have a great great uncle Ernest who was legally married in England in 1905. He and wife went separate ways shortly after the birth of their daughter, who died at 11 months, but they did not divorce.
Ernest went on to marry bigamously in 1914. He was caught and convicted. This seems not to put him off, as he married bigamously to another woman in 1927. He was still legally married to his first wife. He got away with it for about 12 months, but when he proposed to another woman while already bigamously married, and had banns called in two parish churches, his second bigamous wife got suspicious, informed the police, and he was sentenced to another much longer stint in prison. I know these details from various newspaper reports of his trials.
A marriage where one or both parties were already married was legally null and void. However, it is unclear to me whether the innocent party would need to obtain an annulment or declaration of nullity in order to marry again, since a void marriage never actually took place? Would nullity have been implied with conviction for bigamy?