European Union leaders are gathering in Brussels today to grapple with the most immediate consequence of Britain's recent departure from the EU: the hole which the ending of British financial contributions will make in the bloc's operating budget.

And although there are plenty of seemingly logical methods by which the budgetary shortfall created by Britain's decision to leave the EU could be covered by the remaining 27 member-states, the summit today can easily descend into an ugly spat between richer EU members determined to limit their financial contributions, and poorer European countries that see the EU budget as their only chance of catching up with the richer ones.