As we enter a key Brexit endgame week, a few thoughts – informed by game theory – come to mind on the ironies of the British negotiation position and strategy thus far. The basic claim of bargaining theory is that you need a strong ‘reversion point,’ that you can go back to if bargaining fails. Once Article 50 was activated, that was necessarily ‘No Deal’ for the UK. But No Deal is likely self-damaging and certainly divisive. So, it did not and cannot represent a credible reversion point. Without this clear reversion point, one option is to pretend you want something self-damaging – the ‘madman’ approach. For this tactic to work, though, you need to be believed to be ‘mad’ …

On January 15, 2019, Prime Minister Theresa May’s Brexit deal suffered a defeat of historic proportion in the House of Commons: 432 MPs voted against and 202 for the ‘EU Withdrawal Act’, with a staggering margin of 230 votes. But how do the MP positions on May’s deal compare with the constituency-level votes on the 2016 referendum? [i] Notably, almost all the intra-party variation in voting takes place on the Tories’ side of the aisle. Only 3 Labour MPs bucked the party line and voted for the deal, whereas 118 Tories voted against May’s proposal. The plot below shows the distribution of constituency vote on the Brexit referendum by MPs voting either for or against the Brexit deal. The graph …