IF he wasn’t acting in everything already, you might imagine a pensive Benedict Cumberbatch, chewed ballpoint hovering over his list of suspects, murmuring to himself in a shabby, dust-moted office: “Sheridan, Militant … Jones, Plaid … ah yes, McTavish, Scots Nat ...”

Such is the bad spy drama evoked by this week’s disclosure from the National Archives: that during the 80s, MI5 maintained a list of 1420 civil service employees identified as “subversive”, who were closely monitored and kept away from certain jobs and roles.

Among the Trots, communists (the majority), and the fascists, MI5 were also watching 35 “black and Asian extremists”, anarchists (of course), and “Welsh or Scottish nationalists”.

It would be nice to lean back, arms folded complacently, and say, “dearie me, how early Channel Four paranoid drama, all behind us now”. The list was managed by an inter-departmental group called (I kid you not) Subversion in Public Life. Nowadays, we are assured by the Cabinet Office, they are “no longer in operation and no other unit is conducting similar work”. Well, that’s me assured then.

The original list seems to have been triggered by a 1984 computer operator strike at the Department of Health and Social Services, which disrupted millions of payments to recipients. This was perceived as being fomented by Militant Tendency activists.

So would they call that “cyberterror” today? They’d try. Note the frothing Tory MEP David Bannerman earlier this week, proposing that a new Treason Act could apply to citizens “working undemocratically against the UK, through extreme EU loyalty”.

Be careful with those yellow-star-on-blue satirical memes on Instagram, kids (or for that matter, any adult. Or most of Scotland’s working politicians).

The MI5 and Treason Act stories are indeed just a few more lumps in what the ex-BBC presenter Gavin Esler has fabulously called “Brexcrement”, thundering down relentlessly on the stoically indy-minded in Scotland.

But step away from the avalanche, and an equally troubling question arises. What happens in an independent Scotland, when we have to consider the “intelligence” part (as opposed to the “military” part) of our national security?

If we create our indy version of a “security service”, do they eventually (or even just potentially) start scanning our own civil service for “subversives”? If we don’t create it, do we genuinely open up our new country to actual dangers and threats? And if the ultimate answer is, “at least design it as wisely as we can”, how would that be done?

I took a day off to read a lot of the available literature on this topic. It’s surprisingly comprehensive, largely generated in the run-up to the first indyref in 2014, though with some recent updates from CommonWeal’s How To Start A New Country, among others. The ideological spectrum is, I would say, from neutral to indy-friendly (with a strong centre-left, peace-seeking/anti-adventurist bias).

Yet what struck me were the continuities, across this spectrum, about the reality of some kind of security threat to an indy Scotland. There’s a desire to distinguish ourselves from the bombastic rhetoric and willingness-to-intervene of the Westminster government. But what surprised me was the range of people who shrugged their shoulders and said, “we will have to deal with this”.

For example, some of you may know the uproarious and valuable pro-indy blog A Thousand Flowers (“a red sock in the white wash of cyberspace”), notable for their “Wanker of the Week” posts. For a few years now, I have had archived a 2013 piece they ran, titled “Redefining Security and Intelligence in an Independent Scotland” (a guest post by “Cosmopolitan Scum”).

The tone is cheeky, full of Scots words, but evidently very well informed, and does indeed redefine the topic. Yet these paragraphs have always lingered with me: “I’d like to live in a right-on world where there was no need for intelligence agencies – I hope that’s what Scotland is like.

“But we wont be able to change what the world is like – some crazy people might still want to attack us to make some political point, other countries will still seek clandestine means of influence, and some groups might seek to subvert political life outside of the norms of our new politics. So, we’ll need an intelligence capacity to deal with counter-terrorism, counter-espionage, and to protect the political process.”

What precedes these words is a point which much of the literature I’ve read consistently echoes. The demands on an indy-era Scottish security really depends on our foreign policy being based on (as Scum puts it) “dialogue and co-operation, rather than racist exceptionalism and habitual strategic miscalculation”. Not invading Islamic states, for example, and distancing ourselves from previous expeditions might “remove one of the key drivers” of any attack.

Yet Scum’s words are prescient about “defending the political process” and “the norms of our new politics” from countries “seeking clandestine means of influence”. Post Russian electoral interference, Cambridge Analytica and now the overt scheming of American far-righter Steve Bannon in Europe, what needs to be done to defend the processes of Scottish democracy - a bush of flowers which may currently be blooming, but which could easily be poisoned at the roots?

Both attentive nutrifying and active pruning, to briefly continue the metaphor. Former Glasgow University rector Edward Snowden has alerted us to the foolishness of assuming that centrally tracking all of a nation’s (or continent’s) digital communications is a reliable way to identify terror threats.

Our foreign policy stance will reduce threat levels – but a cohesive, trusting, relaxedly multicultural Scotland can contribute to that too. This is an environment where traditional security (and policing) footwork in communities will pay off – much more effectively than trying to pick fragments out of a massive data hose-pipe.

And consider the “real security”, as one expert put it to me, that comes from taking seriously the migrations and food disruptions that planetary warming will accelerate. Or the possible extreme inequalities to come from a badly managed automation. The literature I’m reading is at pains to point out how acutely “dangerous” all these systemic deficiencies are.

There are other pieces of this picture that I find a bit John LeCarre. There’s an interesting paper from Glasgow University’s Colin Atkinson on the “hidden politics of intelligence in Scotland’s independence referendum debate”, based on anonymous conversations in the field.

He suggests that if an independent Scotland wished to join one of the big regimes – like the “Five Eyes” (including New Zealand, the US, UK, Canada and Australia), or GCHQ’s monitoring of data cables that come to land down south, or Nato’s services – we’d have to “develop our security data specialism”.

Which turns out to be, according to Dr Atkinson’s paper, “matters of terrorism and security related to Northern Ireland, or the movement of people and goods through our ports”. Though Atkinson reports that the spooks are sceptical that this intelligence would even be valuable enough to get an independent Scotland into the club.

But would we want to be so deeply into these clubs? For example: to what extent would we wish to be contributing to security networks in which some of the intelligence was extracted through torture? Even in the last few days, we hear of Prestwick Airport being used by the CIA for extraordinary rendition flights, with Police Scotland being blocked from boarding an aircraft.

And if we are hearing about this, then it means at least that sunlight has pierced the security gloom – which may be part of the most reliable solution here. As another security expert suggested to me in correspondence, “if the government is able to watch us, then we should be able to watch them. That means everything from the right to film cops, right up to open access to data, and full transparency”. This is a world where Freedom of Information requests become a thing of the past, and a “Glass Wall” approach is the default for public information.

These tales of MI5 skullduggery may be entertaining in a kind of retro way. But as my correspondent says, with disarming honesty, the question of Scottish security measures in an independent nation “is a tricky one. It’s going to involve a balance somewhere. Where that balance ultimately is, I’m not really sure yet.”

Unlike the spooks shrouded in darkness, however, we citizens should be willing to talk about it in light of day. “Independence o’ mind” shouldn’t stop when Benedict Cumberbatch looks up gloomily from his desk, and murmurs “no further”.