LONDON — Behind in the opinion polls, Scottish Nationalists who are seeking independence from Britain in a referendum next year set out their wish list for a new nation on Tuesday, but made several assertions about their future relations with Britain and international partners that are sharply disputed.

A newly independent Scotland would issue passports, create its own defense force and expel British nuclear submarines from their Scottish bases, according to the 670-page document published by the Scottish government, which is led by the Scottish National Party of Alex Salmond. But the country would stay in NATO and transition smoothly to its own membership in the European Union, the document asserts. And while Scots would claim 90 percent of the revenue from North Sea oil and gas and adopt a written Constitution, they would keep Queen Elizabeth II as head of state and retain the pound sterling as their currency, the document adds.

Some of these assumptions, including an independent Scotland’s right to use the pound, are disputed by London. But the publication of the document, meant as a blueprint for independence, is a milestone on the road to the referendum, scheduled for Sept. 18, 2014, the year of the 700th anniversary of the Battle of Bannockburn, in which Scottish forces routed the English.

“If we vote no, Scotland stands still,” the document said. “A once-in-a-generation opportunity to follow a different path, and choose a new and better direction for our nation, is lost. Decisions about Scotland would remain in the hands of others.”