We had a bit of a debate at the weekend with ITV’s generally pretty decent Scotland correspondent Peter Smith, after he tweeted this:

It wasn’t the curious choice of picture we objected to, nor the fact that the £14.8bn figure is a notional sum which is totally meaningless in the context of an independent Scotland (because it represents a vague estimate of the disaggregated finances of a Scotland that’s inside the UK and subject to UK government policy choices).

Nor was it even the implication that a £14.8bn “black hole” was an inherent permanent feature of the Scottish economy rather than an unusually bad year.

What chafed with us was the idea that it was somehow Nicola Sturgeon’s fault.

A complaint we hear a lot from the Unionist left especially is “Why doesn’t the SNP use the powers it already has to improve the economy/reduce inequality/redistribute wealth/solve Scotland’s centre-half problem/bring back the macaroni pie/whatever?”

It’s one we always answer with “Which powers and what precisely should they do with them?”, at which point the conversation invariably goes very quiet.

Because the fact of the matter is that the devolved Scottish Parliament has almost no powers whatsoever to affect the economy, so it’s a bit unfair to be demanding that Nicola Sturgeon be held responsible for reducing a “deficit” that she doesn’t actually have in the first place (since the Scottish Government isn’t allowed to run a deficit and has to balance its books every year).

Let’s imagine how that conversation might go.

NICOLA STURGEON: Okay, I’ve got an idea. Let’s raise the minimum wage so that people have more money to spend. That’ll generate retail and service-sector growth, which are the biggest areas of the economy.

SCOTTISH GOVERNMENT ADVISOR: Nope, sorry. Minimum-wage law is reserved. Scottish Labour specifically fought against devolving it during the Smith Commission talks, despite the proposal being backed by the STUC.

NS: Oh. Well, maybe there’s another way. Could we reduce VAT to lower prices and bring about the same result?”

SGA: VAT is reserved. So you can’t reduce it to boost consumer spending and you can’t increase it to generate more government revenue either.

NS: Huh. I guess if we made businesses wealthier they might employ more people and create growth that way. Could we maybe cut Corporation Tax to try to draw any of them away from the South-East of England?

SGA: No. Corporation Tax is reserved.

NS: Can we at least get them to pay the tax they owe now, then? Corporate tax avoidance costs billions, can we have a proper crackdown on it and boost the coffers that way?

SGA: Nope, that’s reserved too. Westminster employs ten times as many people chasing a tiny amount in benefit fraud than it does on clawing back far higher sums dodged in tax, and is in fact cutting back even further on HMRC staffing levels. So we can’t do anything about it, and there’s also not much point hoping the UK government does and passes any of the proceeds on to us.

NS: What about fuel duty? If we reduced that and got petrol and diesel prices down it’d be good for nearly everyone – haulage firms, businesses transporting their products and end consumers, who’d once again have more growth-creating money in their pockets.

SGA: Fuel duty is reserved.

NS: Our fabulous new income tax powers?

SGA: Those are essentially useless. Firstly we don’t control the basic personal allowance, the thing that affects every taxpayer. We can fiddle around with the margins of the upper rates but that generates very little and also gets you hammered remorselessly from both sides in the press. Even Labour’s supposedly radical plans for across-the-board increases would only amount to maybe £390m at the most, which is chickenfeed – barely 1% of Holyrood’s budget. That’s not going to plug the gap.

NS: Jeez. Well, can we make some savings somewhere? Nobody on the face of the planet actually wants to invade us, surely we can cut a pile of money out of the defence budget?

SGA: It’s reserved. Plus according to Labour Trident supports more jobs than there are actually people in Scotland, so everyone would be on the dole.

NS: Can we bring in some extra cash from anywhere? What do finance ministers usually do in budgets? They bump up booze and fag tax, right? Can we do that one?

SGA: You know what I’m going to say, don’t you? Here’s the Guardian’s list of the 26 key points in the last UK budget. Basically the only things in the list related to the economy that Holyrood controls in Scotland are stamp duty and business rates, and you’ve already done stuff about those. No dice.

NS: Oil?

NS: Okay, let’s think outside the box. We need to get more people into the country, because everyone knows immigrants contribute more than they take out, and we’ve got plenty room. That could help.

SGA: Immigration is reserved, and the UK government is busting a gut trying to throw out the people who are already here.

NS: Bloody hell. Okay, so what are Scotland’s advantages? We know that we’re really well-off for renewable energy resources, and I noticed that there are eye-wateringly massive subsidies being chucked at that new nuclear power station in Somerset, so presumably we could get something similar to invest in our renewables, yeah?

SGA: You’re really not getting how this works.

And so on, etc. Devolution was never intended to let the Scottish Government run the economy – it was always envisaged as a glorified parish council, handling what are in essence administrative municipal matters like education, health and law. There’s a reason it was originally called the Scottish Executive – it’s not a “government” in any true sense of the word and just calling it one doesn’t change that.

If the UK government gave up control of the economy, Scotland would be independent on the day-to-day level in all but name, and every “revision” of devolved powers that’s been grudgingly conceded since 1999 has set out with the primary goal of ensuring that that didn’t happen. (But hey, have all the road signs and air guns you can eat.)

So to recap: the Scottish Government doesn’t have a deficit (the UK one does, and palms some of it off onto Scotland); if Scotland was independent nobody has the remotest clue how big its deficit would be even to within the nearest £10bn (because it would depend on independence negotiations and a raft of policy choices that haven’t been made yet); and until it is the Scottish Government can – by design – do almost nothing to affect the country’s economy.

Other than that, y’know, yes, it’s a totally fair question.