In the first weeks of their new job, around ten officials of Barnier’s team designed multiple scenarios for how negotiations might end. The outcome in 2020 came close to the best-case scenario imagined in October 2016. The UK left with an Article-50 agreement, which was better than leaving without one. It was definitely better than the worst-case scenario of a UK government gradually violating its obligations to the EU and pulling out without notifying its departure. The Withdrawal Agreement honoured all EU and UK legacy obligations of the membership period, including the money the UK owed and citizens’ rights. The new relationship was a free trade agreement without the UK maintaining elements of the single market or other membership benefits, but with legally binding guarantees on a level playing field. All national administrations in the EU were ready to apply the new provisions by the 1 January 2021, which avoided the need for any phasing mechanisms, unlike what happened in the UK.

How that outcome came about was entirely unexpected. The political pressure from Brexiters on Theresa May in 2017 to keep the process moving forwards, after she lost the elections, weakened her bargaining position on the financial settlement, in the face of an immovable bloc of 27 countries that refused to budge on sequencing. In 2018, May kept the negotiations on Northern Ireland active in parallel to the 2018 talks on the future relationship, which the EU wanted to de-couple. As a result, the 2018 deal conceded a more gradual departure to the UK because of Northern Ireland, with less turbulence for British export and supply chains than what Boris Johnson eventually agreed in 2019 and 2020. After the UK Parliament shot down May’s deal in March 2019, the extension to the Article-50-negotiation period forced the UK to hold European elections in May 2019. An absurd situation, which Juncker, Barnier and many EU leaders had tried to avoid, further polarized British politics between opponents of Brexit and advocates of a harder exit, killing the middle ground which May, a majority of Tory MPs and the Labour Party occupied and ultimately leading to a crushing victory by Boris Johnson in the December 2019 elections.