It's 38 rounds (!) of bare-knuckle, knock down, drag out personal combat between the Irish favorite Morrissey and a nameless Russian sailor, sung by Ewan MacColl with an interesting sort of quaver in the delivery.
The fight in question apparently isn't historical, but John Morrissey (1831-78) was an Irish immigrant, a boxer, gambler, gold prospector and, ultimately, politician. They truly don't make them like that anymore...