I never thought that an abstruse knowledge of Troubles-era Northern Ireland political trivia would be of any practical use - but it seems that I was wrong.
Since Thursday night, the English voters seem to have discovered a few things about the DUP - in particular, that they are opposed to abortion and same-sex marriage. These policies are enough to put them outside the political mainstream and to justify raising the question of whether they are suitable partners for Theresa May as she seeks to pull together a new parliamentary majority. But there is more to the DUP than its social conservatism. English readers might want to know a bit more about the small regional party that has suddenly found itself holding the balance of power in the Commons. These guys are quite unusual in a number of ways.