From an unremarkable property in a disheveled neighborhood not far from Glasgow city center, some spooks of MI5 operate, searching for ripples in Britain¡¯s northern approaches.

Their permanent presence in Scotland, if not their actual residence, isn¡¯t a secret known only to an anointed handful. After all, why wouldn¡¯t there be some surveillance operations based in Scotland¡¯s busiest city and one of the United Kingdom¡¯s most turbulent? They have been there for 10 years or so, but whether they remain following a yes vote in September¡¯s referendum is at the heart of one of the most vexed and intriguing issues surrounding the independence debate.

There are several nuances in Scotland¡¯s political, social and economic landscape that will always separate it from London and the southeast of England. Occasionally these have required special scrutiny from Britain¡¯s intelligence forces, such as the fallout and aftermath of the terror attack on Glasgow airport in 2007.