The hard Brexit scenario assumes that trade between the UK and the EU will be governed by WTO rules, which means that most-favoured-nation tariffs will be imposed on trade between the two. Furthermore, the hard Brexit scenario assumes that the WTO will make less progress on reducing non-tariff barriers than the EU and that, therefore, non-tariff barriers would increase to three-quarters of the reducible barriers faced by US exporters to the EU. Furthermore, the hard Brexit scenario assumes that intra-EU trade costs will fall 40% faster than in the rest of the world, implying that non-tariff barriers within the EU will fall by 12.8%. Finally, this scenario assumes that UK’s contribution to the EU budget will fall by 58%.