There is a simple reason why Boris Johnson and European leaders failed to find common ground over Brexit at last week’s G7 summit. They are not even talking about the same thing.

For the British prime minister, Brexit is a matter of national character that cannot be described in legal documents. For continental politicians, legal texts contain the true meaning of a project that only exists in the real world as a set of rules to be implemented. To Johnson, the withdrawal agreement was a single-use tool for levering himself out of a tight spot. For Brussels, it is the chamber into which Britain levered itself.

That difference will continue to cause friction because it is not a misunderstanding. Johnson knows that legal arguments over the Northern Ireland protocol favour the European position. He chooses not to care. To concede on the principle that any part of the UK is subject to European regulatory standards – the compromise he signed to avoid a land border on the island of Ireland – would be to admit that a portion of sovereignty was conceded in the negotiations.

That would be a stain on his self-image as the man who made a clean break from Brussels. He finds confrontation more appealing, not least because he expects it to achieve more than compliance. Whether that is true depends on how you define achievement.