The British Chambers of Commerce (BCC) reports 85% of UK businesses outside Scotland believe the country should remain part of the UK.

The BCC's sizeable survey sheds some light on how companies in the rest of the UK (rUK) feel and how they might react to different outcomes in September's referendum.

How important is it to heed these views? Elements of this survey raise questions about the extent to which it reflects a genuine engagement with the issues. The director general of the BCC concedes businesses south of the Border remain "less than captivated" by the debate. So comments about the Barnett Formula and whether the Scottish Parliament should be given more powers may be more knee-jerk reaction than considered response.

Yet the rUK will remain a crucial market and trading partner for Scotland if the referendum results in a Yes vote. So it is important to know what present and future partners think. At a basic level, companies in the rUK seem less than impressed with the commercial opportunities offered by Scottish independence.

One of the Scottish Government's key policies is a cut to corporation tax, yet only 6% of companies see this as an opportunity while 63% see no business benefits from Scottish independence at all. The most important finding relates to the vexed currency debate. One-third of firms outside Scotland would want to see a formal currency union between the rUK and an independent Scotland, should the referendum go that way.

Very much related is the finding that, if there is a Yes vote, firms outside Scotland fear problems with cross-border trading, with 47% citing currency arrangements the most serious concern. This is significant.

There have been warnings that a separate Scottish currency would cost hundreds of millions of pounds a year in transaction costs, in addition to one-off set-up costs and possible lost business.

Would some rUK businesses cease to trade with Scottish firms in the event of independence? This seems much less likely if sterling were retained.

This is a significant challenge to the position held by Chancellor George Osborne, his Coalition partners and Labour's Ed Balls. All insist that a currency union is off the table but this seems an increasingly questionable position. There are unanswered questions about how it could be delivered but, if businesses on both sides of the Border demand sterling be shared in some manner, it seems implausible to suggest that it would be non-negotiable, as the Unionist parties at Westminster have said.

The problem is businesses and individuals seem unlikely to receive a straight answer on this before referendum day. Whether voters believe currency union will be negotiable is, ultimately, a leap of faith.

That is a risk businesses south of the Border would prefer not to have to take. This is useful to know. But whether their fears would be realised, or whether independence would bring business opportunities as well as risks, is a judgment call voters in this country will have to make.