British Leaders to Sign Agreement on Scottish Independence Vote LONDON - Prime Minister David Cameron and Alex Salmond, the Scottish first minister, ended months of preliminary sparring on Monday, formally agreeing to the terms for a referendum on independence for Scotland that could dismantle the sometimes uneasy and often uneven partnership between their lands since the Act of Union in 1707. The two men met and shook hands in Edinburgh before and after signing the agreement to hold the vote in the fall of 2014. The ground rules for the ballot have been depicted as a compromise: the vote will offer only a single yes-or-no question on independence, contrary to Mr. Salmond's wishes for a broader choice; and, despite Mr. Cameron's objections, the referendum will be open to voters as young as 16 - two years below the national voting age. But the referendum also represents a high-stakes gamble for both leaders, analysts said. Technically, the agreement simply transferred to the Scottish authorities the power to hold a referendum among Scotland's five million people, but its signing was widely seen as a signature moment in a long drive toward independence by Mr. Salmond, who had pressed for the ballot to be held in 2014, later than Mr. Cameron initially wanted. The year is significant because it is the 700th anniversary of the Battle of Bannockburn, in which a vastly outnumbered Scottish army annihilated the army of King Edward II. Calling the deal the Edinburgh Agreement, Mr. Salmond cast the signing as a triumph, telling reporters it was "a major step forward in Scotland's home rule journey." The signing also foreshadowed a strenuous bid by Mr. Cameron to keep the United Kingdom intact. "Now we've dealt with the process," he said. Now we should get on with the real argument, and I passionately believe Scotland will be better off with the United Kingdom, but also, crucially, the United Kingdom will be better off with Scotland. Let the arguments now be put, and I hope that people will vote to keep this United Kingdom together. The Scottish authorities had initially wanted the referendum to offer two questions: a straight yes or no on independence and an alternative granting greater autonomy and powers to the existing Scottish Parliament and government. But Mr. Cameron insisted on a single question that would force Scottish voters into a clear choice, reflecting a belief that most Scots would oppose a complete break with the rest of Britain. "What we have is one single question, a very simple single question about whether Scotland wants to stay in the United Kingdom or separate itself from the United Kingdom, " Mr. Cameron said. Mr. Salmond has invested much political capital in promoting Scottish independence, while Mr. Cameron does not want history to cast him as the prime minister who oversaw the unraveling of the union, particularly since he is to face the voters to seek a second term in 2015. "I want to be the prime minister who keeps the United Kingdom together," Mr. Cameron said. For his part, Mr. Salmond said the agreement "paves the way for the most important decision our country of Scotland has made in several hundred years." "It is, in that sense," he added, "a historic day for Scotland and a major step forward in Scotland's home rule journey." Asked by a reporter if his intention was to "rip up" the union flag, the Scottish leader replied, "We are interesting in building a new relationship, not in ripping things up." John Curtice, a professor at the University of Strathclyde in Scotland, said recent polling showed about 63 percent of potential voters opposed to independence and 37 percent in favor. But, with two years to go before a vote, it is uncertain whether those numbers will endure in an era of economic austerity and broader uncertainties over issues like Britain's place in the European Union and Mr. Cameron's shaky coalition with the Liberal Democrats. While Mr. Salmond's followers are hoping for a boost from younger voters, Mr. Curtice said 16- and 17-year-olds would account for only around 2.5 percent of the eligible electorate. The battle over independence is likely to be fought on a broad front that includes the economy, with Mr. Salmond's followers saying that access to a greater share of Britain's North Sea oil reserves would more than offset the loss of annual transfer payments from Britain. Supporters of retaining the union are likely to argue that Scotland would have much greater international influence as a part of the United Kingdom than as a stand-alone nation of five million people. "I think these are the issues that people are going to focus on and that will be much more powerful than an uncertain prospect," said Michael Moore, Britain's minister for Scottish affairs. The impetus for a referendum gathered pace last year after Scottish elections in which Mr. Salmond's Scottish National Party won an outright majority in the Scottish Parliament, bringing the party closer to the goal of independence, which it has pursued since its founding almost 80 years ago. But the referendum has sweeping consequences across the political spectrum, particularly for the opposition Labour Party, which would forfeit its electoral support among Scots if Scotland broke away from Britain.