Some Mothers Do 'Ave 'Em (1973)

Season 2: Episode 4

Betty reveals that she's pregnant. Frank goes off to a holiday camp for an interview as a ""bluecoat."" Frank runs through his act as a ventriloquist, using a dummy called Marvin the Monkey. Unfortunately, Marvin's head gets damaged, so Frank replaces it with a doll's head. The manager wants a singer, so Frank gives him an awful rendition of ""Early One Morning"". He finishes his act (and his chance of getting the job) by accidentally setting off a firewaorks display from the back of his coat.