In an article in The Times, David McCann quotes Scottish government advisor Mark Blyth as saying independence would be "Brexit times ten":
“If your argument is that we need to do this because of Brexit, then Scotland separated from England is the biggest Brexit in history,” he said. “The last time Scotland was fully economically independent, the word capitalism hadn’t been uttered.
“It [the Union] has been together for over 300 years. So, if pulling apart 30 years of economic integration with Europe is going to hurt, 300 is going to hurt a lot.
The argument here is that Scotland has been part of the UK for longer than it has been part of the EU, therefore leaving the UK would cause more changes than Brexit.
Scotland has been part of the UK since the union of the parliaments in 1707, so that's 314 years. (Having said that, Scotland did keep its separate legal and education systems.) And Scotland was in the EU or following the EU's rulebook from 1973 to 2020, which is 47 years. So it's absolutely true that Scotland has been in the UK about 7 times longer than the EU.
However, most of the regulations that individuals and businesses follow are recent. In fact the majority are from the last 50 years. This is because in the past countries were poorer, so couldn't afford so much red tape, and life was simpler so the red tape was less necessary.
(As an example of life being simpler, I am writing this on an ordinary desktop computer, which has over 100 billion components. Nothing like this existed in 1707.)
So even though Scotland has been in the UK longer than the EU, that doesn't mean that leaving the UK will involve more regulatory changes that Brexit did.
No Change vs. Massive Disruption
Returning to the article, McCann continues:
“That means one of two things. Either you have brass-plate independence — you declare independence, you get a vote, but nothing really changes, you put up some brass plates in Edinburgh, and nothing really changes, you keep the pound and all that stuff.
“Or you go for regulatory divergence — different currency, different economic policy, etc, which will entail significant short to medium-term costs. There’s no way around that. We know that because it’s Brexit times ten.”
This is the nub of the argument, that independent Scotland has to choose between:
do more-or-less the same as the residual UK so "nothing really changes"
change everything suddenly and have chaos
But this is nonsense. because there's a third possibility, a middle path where we start off aligned with the UK, and things change over time with there being transitional arrangements. I think this is the most likely outcome, because both Scotland and the residual UK (rUK) will be motivated to co-operate. I explained why in my earlier article How Scottish independence negotiations might go:
During the referendum campaign the UK government would no doubt talk tough, telling Scots that if they choose independence, they're on their own and they will get no help or co-operation from the UK, etc. After the referendum result, this rhetoric will be dropped as it will have served its purpose. Instead the new mood, both north and south of the border, would be one of co-operation, because:
(1) Scotland and rUK share an island
(2) they are going to be neighbours whether they get on or not
(3) it's in both countries' interests that they do get on
(4) both countries have a lot in common, such as shared language and culture, which means they will find it easy to co-operate should they choose to do so
(5) all the above points are obvious to everyone
Countries tend to act in their own interests, and it will be in the interests of both newly-independent Scotland and rUK for the two states to co-operate. So they very likely will. This co-operation is likely to include transitional arrangements for all sorts of things, including currency, trade and customs, defence, etc.
The only way this co-operation wouldn't happen would be if politicians (especially in the residual UK) decide to be uncooperative out of spite. In that instance, there would be a degree of friction and temporary disruption, but if the UK was stupid enough to not agree to a withdrawal agreement (with attendant transitional arrangements) then:
UK could forget about Scotland paying any of the UK's massive national debt, since without an agreement, we would not have agreed to do so.
After Scotland rejoins the EU, Scotland will have more power to harm the UK than the other way round. We’re already seen how Ireland (and not UK) has got its way over its border with Northern Ireland, because Ireland is in the EU.
Faslane Naval Base
Returning to the Times article, McCann further says:
According to the interview, published in the Scottish Mail on Sunday, Blyth described Scotland’s economy as small and open and suggested an independent Scotland might need to keep Trident submarines based in the country to secure access to the EU.
He said: “If the first thing you do is basically say to Nato that, ‘We’re not going to host your nukes any more, and your submarine access is cut off, and you can’t dock in our ports’, they’re going to make life very difficult. And if you do that from the European side, don’t expect them to be too forthcoming on EU membership.’
The argument here is that:
UK will want to continue to base its Trident submarines at Faslane.
If Scotland forbids this, Scotland will annoy NATO.
If Scotland annoys NATO, Scotland will find it harder to join EU.
Therefore Scotland will have to put up with UK Trident submarines at Faslane, against the wishes of the Scottish people.
Regarding point (2), I agree.
Regarding point (3), there is a big overlap between NATO and the EU: most NATO members are in the EU, and most EU members are in NATO, so it makes sense for Scotland to join both, in order to be fully part of the European "club". So it's likely that Scotland will join both, and if Scotland is seen to be wanting to join both, then other European countries will see Scotland as more European, so that will make it easier for Scotland to join both.
But regarding point (1), I disagree. I don’t think rUK will want to keep its submarines at Faslane in the long term. Therefore the conclusion (point 4), also fails.
To see why I disagree with point (1), consider the UK's nuclear-armed Trident submarines. These are currently based at Faslane in Scotland, formally Her Majesty's Naval Base Clyde (HMNB Clyde):
If transitional arrangements were in effect, the UK could continue to use this base for a period of time agreed with the Scottish government, in return for paying rent on it. In the long term, the UK would no doubt prefer to base its submarines on its own territory. This is because (1) it has full control over its own territory, and (2) doing things locally means that the wages of the people working at the base get spent in the UK not Scotland.
(If transitional arrangements were not in effect, the base and all its contents would revert to Scottish control on independence day, something the UK government would wish to avoid. The UK might wish to use military force to avoid Scotland getting control of HMNB Clyde, but it is did, this would cause a massive diplomatic row, with both the USA and European countries getting involved.)
An in fact there is already a submarine base in England -- HMNB Devonport near Plymouth, which is also the biggest naval base in Western Europe.
It's therefore very likely that the UK government would relocate the submarines from Faslane to their existing facility at Devonport, rather than attempt to use Faslane permanently.