The famine originated with the recurrent failure of the potato crop: around 1 million died in Ireland as a result either of starvation or—more commonly—disease. The origin of this demographic cataclysm lay with a fungus, phytophtora infestans, which destroyed half the Irish potato crop of 1845, and brought a near total crop failure in 1846. A partial recovery in 1847 was offset by a greatly reduced area under cultivation, so that although there was a good yield per acre sown, the total harvest was poor. The potato crop failed almost totally in 1848.
The Conservative administration of Sir Robert Peel initially tackled the blight with some success, buying Indian meal and establishing food depots. Peel's government fell in June 1846, to be replaced by a more doctrinaire Whig administration. The Whigs relied at first on an extensive scheme of public works, but this was abandoned in 1847, being replaced by soup‐kitchens. The limited crop recovery in 1847 persuaded the government that the emergency had ended, and all special relief programmes were abolished. This apparent British complacency fired later 19th‐cent. Irish nationalism.