The Irish Potato Famine was a major disaster in the 1840s that cost Ireland a quarter of its population and has repercussions to this day both in Ireland and in relations between Britain and the Irish diaspora. The famine happened because the potato crop that the Irish relied on for a very high proportion of their food was devastated by blight. Further the British Conservative government of the time believed in protecting landowners, didn't care about the Irish and taxed food imports into Ireland to protect Tory voting wheat farmers and farm owners.
At least a million Irish people died and another million emigrated as a result of the famine and its mishandling. At the time there was no welfare state but the charities that were trying to feed the starving could have fed more if they hadn't had to pay taxes on the imported food.