Last week saw an unusual event in the UK: a referendum held in one of the constituent parts of a sovereign entity, to decide whether or not to secede from the whole. After an intensive two-year debate, the people of Scotland considered the issue carefully, and opted to preserve the status quo.

A man shows signs of opposing Scotland's independence, in Edinburgh, Britain, Sept. 17, 2014. The Scottish Independence Referendum will take place here on September 18, 2014. [Xinhua/Guo Chunju]

This was an unusual event, but then the United Kingdom is an unusual state. Most countries of the world (or at least pre-twentieth-century ones) are based on the principle of the nation-state, i.e. a sovereign entity representing a single historic people. The U.K. has four constituent parts, of which England is by far the largest, thereby achieving gradual dominance over the others. While Wales and Ireland were integrated by conquest, Scotland joined the union as a result of a bilateral agreement in 1707. Thus Scotland maintains a historical claim to be part of a voluntary union which could be voluntarily dissolved; it is not strictly comparable to other regions in other countries.

READ: Scottish independence: an imperial implosion?

However, the question remained: was separation a good idea? Scotland has some natural advantages, especially a thriving offshore oil industry, which would have underpinned an independent Scottish economy. The example of oil-rich Norway, a country of similar population to Scotland (and one which itself separated from Sweden only in 1905) was often referred to. Scotland, which enjoys devolved powers and a separate legal system, has always maintained a high standard of education and a technology-friendly environment. The pro-independence Scottish regional government made a good case for Scottish economic viability.

But, during the long pre-referendum debate, problems began to emerge. The U.K. has remained outside the European currency zone and retained the British pound: what currency would Scotland use? Access to the pound or to the euro would have to be negotiated, with no guarantee of success. Scotland has no central bank to underwrite its own currency. An independent Scotland would have to negotiate access to all the international organizations of which it is currently a member as part of the U.K. And there might be some opposition to this, not only from the remaining U.K. but also from Spain, which has its own separatist movement in Catalonia to worry about. The strongest argument used by the pro-unity camp, however, was the question of the huge pension funds the U.K. has built up. How would the share due to an independent Scotland be calculated? And would Scotland be able to guarantee the level of pensions due to those who have worked all their lives to earn them? In fact, of course, an agreement could have been reached, given a degree of goodwill, but the uncertainty was enough to frighten Scottish pensioners. While the vote for remaining in the U.K. was 55 percent across Scotland, it was over 70 percent among the over-60s.