text: Barack Obama claimed that this event would send its country to the "back of the queue."
full_question: Barack Obama claimed that this event would send its country to the "back of the queue." Stephen Barclay and David Davis have both served as "secretary of state" for negotiations related to this event, which created the rejected "Chequers Plan" and will likely involve a "Divorce Bill" mandating payments of about fifty billion euros. Following this event, David Cameron resigned as prime minister, and he was replaced by Theresa May. For 10 points, name this event in which an island nation elected to leave a multinational organization.
first_sentence: Barack Obama claimed that this event would send its country to the "back of the queue."