After 47 years of membership, the UK left the European Union on 31 January 2020. A digital clock beamed onto the facade of 10 Downing Street counted down to 11pm, the beginning of a new chapter in EU–UK relations on a profoundly different footing and one yet to find firm ground. During the Brexit negotiations, I was a close aide to Michel Barnier, the European Union's Chief Negotiator from October 2016 until March 2021, and witnessed the whole process with the UK team of Theresa May and then of Boris Johnson. Working for Barnier gave me a ringside seat to all crucial talks as a member of the EU negotiation team. This book is a personal analysis of the Brexit story from that vantage point in Brussels. It does not represent the position of the European Commission.

One motivation for writing this book is that I believe EU civil servants should play an active part in public conversations: openness creates trust. I had privileged access to information of public interest, which I use in this book. The Commission's unprecedented transparency policy for Brexit has made all official papers freely available online since May 2017, including pos-ition papers, internal documents sent to member states and draft legal texts on the terms of withdrawal and the future relationship. There was never a secret as to what the EU wanted. I draw on these sources, hundreds of meetings with national officials and Members of the European Parliament, as well as the media archives of newspapers and magazines quoted in the text, in addition to my own notes of personal discussions with participants at the time. I have eschewed the formality of citations and a bibliography as this is a first-hand account of my lived experience of Brexit. This book tells the inside story of the EU position and reveals how the “Brussels process” worked.

Some authors and commentators mistakenly think that the UK shaped the EU's behaviour and positions during the negotiations, but British politics was either too divided or too disruptive to have an effect on the EU. This book discusses the real rationale for the EU's positions and explains why it acted as it did.