Italy’s pro-euro elites have overreached disastrously. President Sergio Mattarella has asserted the extraordinary precedent that no political movement or constellation of parties can ever take power if they challenge the orthodoxy of monetary union.

He has inadvertently framed events as a battle between the Italian people and an eternal ‘casta’ with foreign loyalties, playing straight into the hands of the insurgent Five Star ‘Grillini’ and anti-euro Lega nationalists.