The Great Famine

Phytophthora infestans destroys the potato crop from 1845, and roughly a million die of starvation and disease while a further million emigrate — Ireland's population has never recovered its pre-famine level. Grain and livestock continued to be exported throughout under military guard. The British government's response, constrained by laissez-faire doctrine, is widely regarded as a catastrophic policy failure and by many as culpable.