That revenue is significant. In the 2011-2012 financial year it amounted to about $18 billion, according to Britain's Department of Energy and Climate Change.
The independence campaign, which took a major step forward Monday with the announcement that the rules for a 2014 referendum on the matter had been agreed to, has so far appeared to revolve around more abstract issues of cultural identity, national pride, sovereign security and European Union membership. But recent developments -- not the least being the fact the nationalists are lagging badly in the opinion polls -- suggest pro-independence politicians are likely to increase their focus on dollars-and-cents issues regarding the control of energy exploration royalties.
"It's Scotland's oil," a pro-independence slogan from the 1970s, could see a comeback. First Minister Alex Salmond, a former energy economist who is leading the nationalist charge on behalf of his governing Scottish National Party, said Monday in Edinburgh that he has begun "working positively for a yes vote in 2014."
Salmond stated independence is "the means to create a fairer and more prosperous Scotland.”
The majority of Salmond's countrymen don't necessarily agree with him. According to German newscaster Deutsche Welle, polls have long showed only 30 to 40 percent of Scots agree with the idea of creating a separate Scottish state.
The main reservations voiced have to do with the uncertainty that would follow a declaration of independence, including whether Scotland would automatically become part of the European Union or would have to apply to join, and not necessarily with disagreement of the SNP's proclamation that a sovereign Scotland would be in better fiscal shape if it were to separate from England.
"Scotland funds a large part of the U.K. through North Sea oil revenues," SNP Deputy Leader Nicola Sturgeon told Deutsche Welle on Monday, adding that "other small European countries that don't have the resources that Scotland has, manage to be independent -- and to be successfully independent. And that's the future we want for Scotland as well."
Oil revenues are not the only economic issue that is likely to be in play. Others have suggested the question of what would happen to the Scottish banks -- the largest of which was nationalized by the British government in the midst of the 2008 financial crisis -- is likely to loom large in future debates.
But there is little doubt that energy royalties, which are already at the fore of Scottish politics as the Edinburgh government invests in both oil and gas exploration as well as alternative energy sources, are poised to become a major bone of contention in coming discussions.
One possibility is that no matter what happens in the referendum, nationalists will push to have the Scottish government get more of the oil and gas royalties.
In the agreement between Edinburgh and London signed Monday to set the rules for the vote, one of the points both sides acquiesed to was having the electoral question set up as a yes-or-no vote on independence. Previously, it had been suggested voters would face a two-part ballot that asked them to vote both on independence and on demanding fiscal sovereignity -- but not separation -- from the United Kingdom. The latter status option is known as maximum devolution, or "devo max," in Scottish politics, and keeping it off the ballot was widely interpreted as a victory for those campaigning against Scottish independence.
But it's also possible that even if independence is roundly defeated at the polls, the political environment created by the campaign leading up to the vote could favor further steps towards "devo max," and increased oil riches.
On Monday, British Prime Minister David Cameron suggested Westminster Palace would be amenable to such a path, as long as the Scots stop short of outright independence.
"Those who want to see not only the status quo but further devolution from the United Kingdom to Scotland must vote to stay within the United Kingdom," Cameron said.