1860. Brothers Fred and Joe Saunders leave the mining village of Leybourne and walk to London with the aim of meeting the famous boxer Tom Sayers. They hope to persuade him to test out Fred's boxing talents to see if he can trade working down the pits for a life in the ring. The pair enter the Elephant and Castle pub, Sayers' evening haunt, and while Fred spars with the boxer in the yard Joe starts singing to entertain the drinkers. The song, A Half of Half and Half, goes down well with the pub's clientele and the landlord offers Joe £1 a week to sing each evening. The news for Fred is not so good - Sayers tells the miner that a life down the pits has ruined his health and as a result he'll not make it in the ring. Joe opts to stay in London in the hope of raising enough money to get his brother out of the mines - in the meantime Fred returns home to a life of digging coal.
News of Joe's singing ability reaches Bessie Bellwood, owner of the Mogador music hall, who invites him to perform. Unfortunately, his choice of song fails to win over the audience. Bessie tells him he's not good enough and offers him a farewell drink. Joe declines, but the thought of alcohol launches him into song, a rousing chorus of A Half of Half and Half. Bessie likes what she hears and invites him back for a second chance. However, as he died on stage under his own name he'll have to perform under a pseudonym - George Leybourne.
The Great Vance, an established comedy singer, hears about Leybourne's repertoire of drinking songs and tells him to stop as they are part of his own act - a warning that goes unheeded. As a result, the two singers try to outdo each in verse, each adding stronger drinks to their lyrics in an attempt to better the other. Beer gives way to gin, port, rum, brandy and finally champagne. Vance, infuriated by Leybourne's refusal to back down, challenges him to a duel using pistols. Fortunately, neither has ever used a gun before and no one gets hurt.
Bessie's daughter Dolly, meanwhile, has caught the eye of Lord Petersfield, who becomes besotted with the young dancer, but their courtship seems doomed as a marriage between a music hall entertainer and a Lord would be socially unacceptable. This fails to deter Petersfield from pursuing the relationship despite a blanket refusal from his father, the Duke, to let him marry beneath him.
At first Bessie seems pleased with the Duke's intervention, but her daughter's obvious distress wins her around. She sets off to visit the Duke, who was once her suitor but was dissuaded from marrying the young Bessie by his own father. She reminds him of past events but the Duke still won't sanction the wedding of his son to a dancer. Before leaving, Bessie discovers that the Duke is heading an enquiry into the music halls which could get them all closed because of their rowdy nature.
A fight breaks out at the Mogador, started by the theatre owners who want the halls shut down, but before the police arrive Sayers and some of his friends restore order. Unfortunately, news of the fracas reaches the enquiry - the future of the music halls now seems sealed.
Bessie, Vance and Leybourne take to the stage in a show of unity, perhaps for the last time. As they start to sing the Duke arrives with good news: the halls can stay open. He has also had a change of heart about his son's relationship with Dolly.
