During the long reign of his grandson, George III, Britain's American colonies were lost, the former colonies having formed the United States of America, but British influence elsewhere in the world continued to grow, and the United Kingdom of Great Britain and Ireland was created by the Acts of Union 1800.
Pada masa pemerintahan lama cucunya, George III, koloni-koloni Amerika milik Inggris lepas, bekas koloni-koloni tersebut membentuk Amerika Serikat, namun pengaruh Inggris di belahan dunia lainnya tetap bertumbuh, dan Kerajaan Bersatu Britania Raya dan Irlandia dibentuk oleh Undang-Undang Uni 1800.