For the great mass of the people of Ireland, subsistence was made possible by one thing alone, the potato. Described by modern nutritionists as the one staple food capable of sustaining life as a sole diet, the potato had been common in Ireland since the seventeenth century, and was already at that point identified with Ireland in the eyes of some foreigners: anti-Irish mobs in seventeenth-century England are described as having used a potato impaled on a stick to represent the Irish.
At that time, however, and during the early part of the eighteenth century, the potato formed only the basic part of a diet which also included milk, buttermilk, eggs, fish, and meat for the better-off. As the pressures of population grew through the last part of the eighteenth century and into the nineteenth century, for large numbers of people it went from being an important food to being the only food. Since a single acre of potatoes could feed a family of six, it was the basis of survival for the very poorest.
Contemporary accounts describe the Irish eating huge quantities, an average, according to contemporary statistics, of ten pounds a day per person.
Partial failures of the potato crop, and resulting local famines, were relatively common up to the 1840s. In 1845, however, a previously unknown blight appeared without warning, and destroyed the potatoes so rapidly that terror spread throughout the countryside. "The air was laden with a sickly odour of decay, as if the hand of death had stricken the potato field, and everything growing in it was rotten."
That year, only 30 to 40 percent of the crop was actually destroyed and though there was great suffering, few starved; people ate food normally sold to pay rent, pawned clothes, depended on public relief. All of these could be only temporary measures, and everything depended on the following year's crop. In late July and early August 1846, the blight returned, and this time, with astonishing rapidity, it destroyed almost the entire potato crop.
Less than one fifth of the harvest survived. In 1847, although the blight eased, so few potatoes were sown that the harvest was only 10 per cent of the 1844 level.
Encouraged by the relative healthiness of the 1847 crop, mass planting took place once more, but the blight returned in full force in 1848, with the countryside "from sea to sea one mass of unvaried rottenness and decay". Blight continued to ravage the crop for the following six years, and it was only in 1855 that the total harvest reached more than half of what it had been in 1844.
From the summer of 1846 on, the blight brought immediate and horrible distress. One historian estimates that between 1.1 and 1.5 million people died of starvation and famine-related diseases, and scenes of unimaginable mass suffering were witnessed: "cowering wretches almost naked in the savage weather, prowling in turnip fields and endeavouring to grub up roots", "famished and ghastly skeletons, such as no words can describe", "little children, their limbs fleshless, their faces bloated, yet wrinkled and of a pale greenish hue". Deaths were highest in south Ulster, west Munster and Connacht, those parts of the country where the population of poorest subsistence farmers and labourers was most dense, but very few areas escaped entirely. All over the country landless labourers died in their tens of thousands, and even shopkeepers, townspeople, and relatively comfortable farmers perished from the effects of the diseases spread by the starving and destitute.
Although the blight itself was unavoidable, its impact on Ireland was magnified by the response of the British government. Blinkered by free-market dogma, and by a profound, almost malevolent, indifference to Irish ills, the government refused to recognize the scale of the disaster or to provide public assistance above the level existing before 1844. Only after the horrors of the winter of 1847, when world opinion made it impossible to ignore the magnitude of the cataclysm occurring in Ireland, were efforts finally made to organize public relief. Even then, these efforts were hampered by slavish adherence to the ideas of the free-marketeers: the poor could not be allowed to become dependent on the state and, above all, the market itself should not be interfered with. As a result, thousands of starving people were put to work, for barely enough to keep them alive from day to day, on projects with no practical value, unnecessary bridges, roads that led from nowhere to nowhere.