Yesterday I went to visit Scotland’s oldest family-owned business. In their industrial unit in Auchtermuchty, Fife, they have a pair of iron beam scales (a simple weighing device) stamped with the date 1715. These are presumed to have been made by the founder, John White, an entrepreneurial blacksmith who is the great-great-great-great-great-grandfather of the present managing director, Edwin (Ted) White.

300 years later, John White & Son remain scalemakers, though the founder would scarcely recognise today’s products which range from precision digital laboratory scales to electronic weighbridges. Nevertheless, it’s still a family business and it seems remarkable to me that seven successive generations of sons should have followed their fathers into it.

Part of my mission is to find out what motivated them to do so; another part is to find out how they were able to avoid the three-generation cycle of make it-build-it-spend-it that besets so many family enterprises; another still to understand how they continue to survive in an era when the average lifespan of a business is 14 years.

Yesterday’s visit was a preliminary fact-finding mission for a chapter I will write in a forthcoming Dark Angels book about very old businesses. It’s an idea of Stuart’s that’s been kicking around for a couple of years, and its moment came this summer when we met with our nine new associates to discuss the future of Dark Angels. Each of us has chosen a business to investigate and we aim for the book to appear next year with the working title How On Earth Have You Managed It? The 12 subjects range from global brands such as Guinness to small family firms like Whites.

I had never heard of Whites until I got onto Google. I was keen to find a Scottish business, and Stuart had already bagged Scotland’s oldest, The Shore Porters Society, the removals firm that began life at Aberdeen harbour in 1498. When I came across Whites it was the direct line of family succession that intrigued me as much as the age, although the fact of their tercentary is something of a bonus, and I was also amused by the resonance of their founding in the year of the first Jacobite uprising, when we’re now a year on from the Scottish independence referendum.

I was also drawn by Whites’ location. The small town of Auchtermuchty is a couple of miles north of the even smaller town of Falkland, which sits in the northern lea of the Paps of Fife, as the twin peaks of the Lomond Hills are known. Falkland is where Sarah and I spent our first winter back in Scotland, in 1990. Having moved from London we were looking to buy a house and we ended up renting there.

Moncrieff House is a tall stone building that stands on the high street, opposite Falkland Palace, the hunting palace of the Stewart kings and a Renaissance treasure. The house was built in 1610 by James VI’s cup-bearer, Nicol Moncrieff, as evidenced by the gilded inscription set into the wall above the front door. Very unusually for Scotland, the house is thatched. When we were there it also lacked central heating and boasted what we joked must still be the original plumbing. Christmas 1990/91 was very snowy and we spent the days lighting fires in every room we could. It was a magical first winter back in Scotland.

At that time our daughter Anna was 18 months old and Sarah, heavily pregnant with our son Jake, was still running her textile design business. We needed occasional childcare, and it so happened that Tio, the previous tenant at Moncrieff House, an artist and single mum with four small boys who had moved up the road to Auchtermuchty, was happy to help out.

The following spring we moved to the house we had bought. We kept in touch with her for a while but eventually lost contact. But it’s surprising how often the rule of six degrees of separation comes into play; and in Scotland, with a population of just five million, it often feels more like three or even two degrees. And so it turned out with Tio. Since 1994 she has been Ted White’s wife and a director of John White & Son.