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 and an Irish revolution in 1798, and near-constant war with France.

The 20th century sees partition in Ireland. A sense of national unity emerges in the aftermath of the Second World War, but economic challenges in the 1970s create new divisions and questions about the union's future.