Imagine the following: the prime minister invites the leaders of France and Germany to join him in teaching his voters about the merits of the EU constitution. That will happen this month, but the premier in question is Spanish. The festivities in Barcelona on 11 February are not confined to Jose Luis Rodriguez Zapatero and his guests Jacques Chirac and Gerhard Schroder. Johann Cruyff, the Dutch manager of the city's famous football team, will also be on hand. At a Madrid derby match last month, rival fans were given booklets explaining the treaty. On the eve of the 20 February vote, schools will hold a Europe Day. Spain, the first of a dozen countries to hold a referendum, is expecting a high turnout and a convincing victory for the Yes …