The honest answer, of course, is no-one has the faintest idea. But we can have a guess.
In the short term it could well push up the cost of borrowing for everyone: with a likely 18 months or more to resolve the terms of separation, that opens up a long period of uncertainty, which the markets hate.
Ironically, that very uncertainty may well discourage the Bank of England from increasing base rate: the possible ramifications are unfathomable but certainly include the risk of weakening recovery, which the Bank would be reluctant to damage further.
Will it be harder for Scots to get mortgages? Probably not significantly. Despite warnings that big brands such as Lloyds and RBS will move their official base to England, they’re not likely to stop lending north of the border. Smaller institutions, however, may feel it’s safer to stop for a while until the picture is clearer.
Current homeowners in Scotland could be in for a bit of a roller coaster ride until the currency question is sorted out. A currency union would mean everything carries on as normal – but given the hostility coming out of Westminster you can’t take that for granted.
But if a mortgage is held in sterling (as opposed to Stirling haha!) and wages earned in the Hibernian Dollar, exchange rate fluctuations may have a significant impact.
Alternatively, lenders could choose to ring-fence Scottish loans and convert them into a new currency, while leaving the rest in sterling – effectively creating a Scottish subsidiary. Standard Life (no longer a lender) has outlined a plan along these lines for savings and pension customers.
As already noted, the cost of borrowing will likely be higher in any case – and one would suppose that as a new nation, Scotland would naturally face higher costs until she demonstrates her creditworthiness over a period of time.
Would a Scottish subsidiary lender therefore have higher rates – possibly even higher standard variable rates – than its UK parent? You couldn’t rule it out.
Any Scots thinking about voting Yes may also want to think about getting a fixed rate.