In their darkest moments, City financiers imagine a post-Brexit London that is a shell of its former self, transformed from a contender for the title of world’s premier financial hub into an also-ran dotted with shrunken regional offices. That is unlikely but not impossible, and with the UK still stuck in Brexit purgatory, the City needs to make its voice heard in Westminster as loudly as it can, or risk ending up like Montreal.

Quests for greater sovereignty can be ruinously expensive, and exhibit A in the case of how badly they can turn out is Montreal in the 1970s. Quebec’s dream of being an independent country and “masters in their own house” led to many head offices and much of the Canadian financial sector upping sticks and fleeing the province for Toronto.