london britain opposition labour party call prime minister theresa may tuesday put post-brexit membership single market customs union discussion talk european union embarrassment last 24 hours give new mean phrase coalition chaos labour brexit spokesman keir starmer tell parliament tentative deal brussels dash last minute monday prime minister rethink reckless red line put options customs union single market back table negotiation starmer ask speak northern ireland brexit minister david davis say suggestion british government would leave one part unite kingdom customs union wrong britain 's labour say may consider keep uk eu customs union single market