Scots business has not been wholly opposed to secession from the UK. Large figures in a relatively small world, such as Sir Brian Souter, the bus and train entrepreneur, and Tony Banks, developer of a large care home business, have been enthusiasts for the cause. But most business people have been sceptical, though quietly so.

To take up arms against nationalism and, by opposing, hope to diminish it has been generally seen as ill-advised. Some are in retail businesses and feel a need to avoid giving offence. Others rely on government contracts. Those in the media can fear being thought biased. All these factors deter critics of independence from speaking out.

The few who do speak, tweet or post, talk of some harassment, as I have found in conversations — usually anonymous, at their request — with many business people. One forceful tweeter against the Scottish National party, who also asked to remain anonymous, lost the board membership of a charity due to feared loss of government support. Another instanced a friend who said open opposition would force him to fire 50 workers, as loss of government work would follow.

Still another, a financier with a large farm, told me he was constantly investigated by various authorities, while a nationalist neighbour’s farm attracted no attention. If true, these episodes are enough to discourage most people from further complaint. They are also grossly undemocratic.

Business scepticism is based largely on the economic case against secession. As the May 6 election for Scotland’s parliament approaches, a raft of reports are warning of a period of austerity, inflicted not by Westminster — a constant theme in SNP rhetoric — but by an independent Scottish government.

The party’s present economic programme is based on work by the SNP-funded Sustainable Growth Commission, published in 2018. It advises retaining sterling as Scotland’s currency for up to a decade after independence, a policy much disliked by party activists. It would mean Scotland had a currency over which it had no control — and thus could not, as it might wish to, devalue.

The independent state would lose subsidies from the UK Treasury amounting to £1,633 a year per person, according to a Financial Times analysis. Annual tax rises or spending cuts equivalent to £1,765 per person would be needed to reduce a budget deficit, currently running at almost 10 per cent of annual economic output, to the EU’s 3 per cent ceiling.

Another report, from the Institute for Government, estimated that unpicking Scotland’s 1707 union with England and negotiating EU membership could take a decade. A hard border between Scotland and the rest of the UK, which takes around 60 per cent of Scottish exports, would be “the inevitable result” of Scottish EU membership, the report said.

Many business people believe Nicola Sturgeon, Scotland’s first minister, is ill-disposed to business. One entrepreneur who set out to her the economic downsides of secession got the reply: “I am a conviction politician.” The pursuit of independence trumps all else.

This scorn makes business people angry. They think they are cast as Scots Scrooges, indifferent to poverty and inequality. Jim McColl, founder and chief executive of Clyde Blowers Capital, an engineering and investment group, says: “There’s a feeling that people who have businesses don’t want social programmes. Business people do want these — they’re all for levelling up. But you can’t fund all the social programmes without business thriving.”

The gulf between business and pro-independence politicians is arguably wider than ever. But Sturgeon is right: “conviction politicians” who seek fundamental constitutional change must possess a rare belief in self, party and people. Such a belief must shrug off ordinary people’s daily concerns.

Sturgeon’s steely determination has been strengthened by an inquiry that cleared her of misleading the Scottish parliament. Yet qualms in her party persist. In a leaked video of briefings given by two SNP ministers to activists, one conceded that the currency issue could hobble a post-independence government. The other told his audience not to be pulled into a discussion on currency, but state that the SNP believed in keeping sterling and move on.

Her latest challenge is from her one-time mentor, now embittered opponent Alex Salmond, first minister from 2007 to 2014. He portrays his new Alba party as a way of increasing support for nationalism, but it may hurt the SNP’s chances of winning an outright majority in the Scottish parliament.

Business people are rarely political zealots. Scots in business, inventors, economists and philosophers have changed the world — but that was mainly in the 18th and 19th centuries, when Britain and its empire, in which Scots were hyperactive, were growing strongly. Now, most find the grind of maintaining and developing complex companies enough of a day’s hard work.

In Walter Scott’s novel Rob Roy (1817), a Glasgow merchant, Baillie Nicol Jarvie, scornful of opponents of the union with England, says “it’s an ill wind blaws naebody gude . . . what was ever like to gar [make] us flourish like the sugar and tobacco trade? Will onybody tell me that, and grumble at the treaty that opened us a road west-awa’ yonder?”

It would be a rare Glasgow merchant who spoke in these terms today, not least because sugar and tobacco were products of slave labour. But many would quietly admit that the union opened Scotland up, and fear that independence, coupled with Brexit, would to some degree close them off from their large and lucrative market to the south.