The British Prime Minister during the American Revolutionary War was Lord Frederick North, who served from 1770 to 1782. His administration faced increasing unrest in the American colonies due to various taxations and trade policies imposed by Britain, which were met with growing resistance among colonists. North's government struggled to find a solution to the escalating conflict, and he is often criticized for his inability to effectively manage the colonies' grievances. The challenges culminated in the outbreak of the Revolutionary War, leading to Britain's eventual defeat and the recognition of American independence. North resigned shortly after the war ended in 1782.