In this remarkable book, Carmen Callil discovers the story of her British ancestors, beginning with her great-great grandmother Sary Lacey, born in 1808, an impoverished stocking frame worker. Through detailed research, we follow Sary from slum to tenement and from pregnancy to pregnancy. We also meet George Conquest, a canal worker and the father of one of Sary's children. George was sentenced - for a minor theft - to seven years' transportation to Australia, where he faced the extraordinary brutality of convict life.

But for George, as for so many disenfranchised British people like him, Australia turned out to be his Happy Day. He survived, prospered and eventually returned to England, where he met Sary again, after nearly thirty years. He brought her out to Australia, and they were never parted again.

A miracle of research and fuelled by righteous anger, Oh Happy Day is a story of Empire, migration and the inequality and injustice of nineteenth-century England.