Long summer queues at the border risk becoming the “new normal” after Brexit, holidaymakers have been warned, as a fierce diplomatic row erupted with France over the lengthy tailbacks affecting Dover. Both Tory leadership candidates rushed to blame a shortage of French border staff for delays that saw some travellers waiting for hours. Former chancellor Rishi Sunak said the French “need to stop blaming Brexit and start getting the staff required to match demand”. Foreign secretary Liz Truss said she was in touch with her French counterparts, blaming a “lack of resources at the border”.