Brussels (AFP) - British Prime Minister David Cameron interrupted an EU summit on Friday to demand an emergency finance ministers meeting over a demand from Brussels for an extra 2.1 billion euros from London, sources said.Cameron's demand came hours after the European Commission said that Britain had to pay the money, equivalent to $2.6 billion, under new budgetary rules because its economy is thriving while Europe's stalls."He made an intervention at the council," a British government source told AFP, referring to the European Council meeting of the 28 EU heads of state and government in Brussels on Friday."They had quite a bit of discussion on it.