Who exactly is supposed to deliver them, and what are the results? You keep electing parliaments that negotiate specific deals and then loudly, angrily denounce

Who exactly is supposed to deliver them, and what are the results? You keep electing parliaments that negotiate specific deals and then loudly, angrily denounce those same deals. (And I'm not just talking about the Remainers. I'm talking about the ostensibly pro-Brexit party.)