Relations between the EU and the UK risk further deterioration after the Brexit minister accused Brussels of behaving “without regard to the huge political, economic and identity sensitivities” in Northern Ireland. David Frost said the bloc had “destroyed cross-community consent” with an “overly strict” enforcement of the arrangements hammered out in the withdrawal agreement of January 2020. His comments, in a foreword to a new paper for the Policy Exchange thinktank, were published days after a second week of talks between both sides ended in deadlock. He also articulated, in the plainest terms yet, a view held in Downing Street that the protocol’s terms were foisted upon Britain owing to the weakness of Theresa May in the first phase of negotiations in 2017. Lord Frost said the EU-UK joint report, which set the terms for the article 50 process of divorce from the EU, was a result of the UK failing to make “the necessary mental shift from being a member of the EU to negotiating exit from the EU”. The joint report was a landmark moment in the history of Brexit, marked by the humiliation of May by Northern Ireland’s Democratic Unionist party in December 2017 just as she was about to co-sign it with the European Commission president Jean-Claude Juncker. The then-DUP leader Arlene Foster, who was propping up May’s government, told her she would not support clauses which meant Northern Ireland would remain in regulatory alignment with the republic if the border problem could not be solved in second phase of negotiations. Days later the section of the joint report was changed to accommodate the DUP but the sequencing of Brexit was set in stone, putting the Irish border solutions into the legally binding withdrawal agreement – Dublin’s point of maximum leverage – rather than future trade relations. The faultlines generated by the sequencing appear to be driving Frost’s demands for fundamental changes to the protocol. He says he considered resigning from his role as foreign affairs special adviser to Boris Johnson, then foreign secretary, after reading the terms of the joint report and realising “a crucial pass had been sold”. Frost said the protocol agreed that December was a result of the “extreme weakness” of the UK government after the June 2017 election. “We must return to the protocol and deliver a more robust, and more balanced, outcome than we could in 2019.” The Policy Exchange paper – The Northern Ireland Protocol: the origins of the current crisis, by Roderick Crawford – provides a chronology of Brexit negotiations and what went wrong in 2017. It argues that commitments, particularly on the Irish border, in the joint report were “a diplomatic triumph for Ireland and the Commission” but that “failing to secure adequate reciprocal concessions was a staggering failure for the UK”.