Is Britain about to break up? This is no longer a rhetorical question. A referendum on independence for Scotland has been called for Sept. 18, 2014. If the vote is in favor, Scotland could become an independent country on March 24, 2016. This would mean the end of the United Kingdom of Great Britain and Northern Ireland as now constituted.

Current opinion polls suggest that the majority of voters in Scotland have yet to be convinced of the case for independence put forward by Alex Salmond, Scotland's first minister and leader of the Scottish National Party. But opinions could change in the months running up to the referendum, and the British government must consider the implications.

Scotland has a population of some 5.25 million — just under 10 percent of the total U.K. population of about 63.5 million. But population is only one factor. Most of the U.K. share of North Sea oil is found in waters that Scotland could claim and Aberdeen is a major oil industry center.