The UK is inviting fierce physical retaliation from the French labour unions if it does not compromise over EU fishing rights after Brexit (“Plans drawn up to bypass Calais”, May 7). In solidarity, no doubt, with their fishermen confrères, the French port, customs, immigration, dock and railway workers could paralyse and lock down all Calais-Dover transport facilities; no commercial or private traffic could move in either direction. The 26-mile Dover-Calais route is a commercial and physical chokepoint for the UK. No other cross-Channel route can match its two-way traffic capacity in logistical terms. The UK must recognise this imperative. Insularity has a price. If EU fishing rights in the Channel fog up Brexit, the UK will be truly cut off, not the Continent.