In 1603, King James VI of Scotland became King James I of England. The two bitter enemies finally shared a monarch. But, as David Olusoga discovers, the era was defined by religious and cultural divisions. By the end of the century, Scotland led a failed colonial expedition to Panama that was so disastrous, the nation joined with England and Wales to form Great Britain.

What does it mean to be British? And what characteristics define the British psyche? Historian David Olusoga reveals how, in the 18th century, a new British identity was forged in the face of multiple threats from within, including the Jacobite rebellions in Scotland, an Irish revolution in 1798 and near-constant war with France. Out of these conflicts, a new vision of Britishness emerged.

In the 19th century, the union of Great Britain and Ireland appeared to be secure and powerful. Yet beneath the surface were deep divisions between rich and poor, and social class began to define identities and loyalties. And as historian David Olusoga reveals, the greatest disaster in the history of the union was soon unfolding in Ireland: the Great Famine.

A new sense of national unity emerged in Great Britain in the aftermath of the Second World War. But economic challenges in the 1970s created new divisions and questions about the union's future. Historian David Olusoga looks back at the recent industrial turmoil and social change in Britain. With independence causes gaining traction, what does the future hold for the United Kingdom?