Tremors over a possible breakup of the United Kingdom have been felt here in recent days, as markets gyrate and banks make contingency plans. Yet as Scotland nears its vote on whether to be an independent nation, bankers here worry that a split might unintentionally set in motion a push for what could be a much uglier divorce: an exit of Britain from the European Union. “There’s a sense of, ‘If it could happen in Scotland, it could happen in the U.K.,’ ” said Chris Cummings, chief executive of TheCityUK, a lobbying group for the financial sector. If an independent Scotland would be complicated, a Britain alone in Europe would be a complete […]