Tony Osborne London

In 2014, the people of Scotland will be asked whether their country should become independent. A “yes” response will have dramatic consequences for the defense of the British Isles.

Since 1707, Scotland has been a part of the United Kingdom and has almost always been governed centrally from London. But the creation of a devolved government in 1999 and the 2011 swearing in of a nationalist administration has accelerated the march to independence. Under Scottish National Party (SNP) plans, an independent Scotland would keep sterling as its currency—at least initially—and retain the queen as its head of state. Though a close relationship with England seems solid, defense remains something of a sticking point.

Since the 1960s, the U.K.'s submarine-based nuclear deterrent has been situated on the highly guarded Faslane Naval Base. Four Vanguard-class submarines, each capable of carrying 16 Trident submarine-launched ballistic missiles, maintain a constant vigil. But the SNP has a rigorous non-nuclear weapons policy and wants the Trident system withdrawn as early as possible.

This could prove precarious, because “unlike most nuclear powers, the U.K. has just one single delivery method for its nuclear weapons,” says Prof. Malcolm Chalmers, an expert on U.K. defense policy at the Royal United Services Institute think tank. “If it wanted to be belligerent, an independent Scotland could demand the removal of Trident and the U.K. would have no choice but to unilaterally disarm, because there is no alternative [site to house the subs].

“If we still had an airborne nuclear deterrent . . .we would have simply moved the aircraft and the weapons to another base in England, but the infrastructure for these submarines has been built up over time to very specific standards . . . ,” adds Chalmers. It would take more than a decade to recreate the infrastructure, he says.

Such a “radical” move is unlikely, as it would upset NATO and European Union members. Until October 2012, the SNP was anti-NATO because it felt the organization was a “nuclear weapons-based alliance,” but the party now feels it could be a member of NATO's “Partnership for Peace” program.

Chalmers believes that Scotland will take a cautious approach, urging that the nuclear weapons be moved at London's earliest convenience. That might make some Scots unhappy, but at least they will no longer be paying for the system or the multibillion-pound program that will eventually replace it.