I once shared a car to the airport with a French MEP, a member of the Front National (FN). He spoke that very correct French which, across the Channel, serves in place of accent as a social signifier. He casually mentioned that the Holocaust couldn’t have happened, at least not on the scale claimed: the volume of the ovens, he creepily explained, was insufficient. The European Parliament has always had its fair share of extremists, eccentrics and outright, drooling loons. With the FN then polling at 6 per cent, there seemed no need to treat any of its MEPs seriously,...