The rags-to-riches story of the Pathak family, who fled Kenya with nothing and rebuilt a food business to much greater success in their new country, is an inspiration to all immigrants and a pat on the back for Britain as a land of opportunity.

However, this week’s sale of the Patak spices and ingredients business to Associated British Foods (ABF) tells us more about the buyer. ABF was reportedly not the highest bidder (exact terms have not been revealed) but the Pathak family were attracted by allying with another family business. ABF’s founding Weston clan still owns 54 per cent of the £7.3 billion group. That is highly significant, because otherwise ABF would not exist.

Its current mix of commodity foods, the original bread business and later sugar manufacture, along with well-known grocery brands such as Twinings tea and Ryvita and the latest venture into retailing, is unconventional and superficially unpromising. It is a standing offence to any tidy-minded investment analyst or fund manager, let alone the army of investment bankers who cook up schemes to break up companies and put them back together according to the latest fad. Many funds would not touch a business in which they have no ultimate power.

RHM, formerly Rank Hovis MacDougall, the rival UK bakery, has been sold and repackaged so often in attempts to extract super returns from a basic business that it is hard to keep pace. It is now owned by up-and-coming Premier Foods.

ABF does not make sense as an international brands company, either – it owns brands in some territories but not others. For instance, part of the Patak deal was to allow the family to keep its nascent business in India, while taking over the running of ABF’s main ethnic foods division.

The biggest attraction for the Pathaks, however, was surely that the Westons are long-term owners and builders, not the kind who immediately declare a business noncore if it has a bad year. They do sell after making strategic judgments. In 2000 they got out of biscuits. Much earlier they sold the supermarket business that they pioneered in Britain.

ABF is in many ways the opposite of private equity. Yet it does share certain useful characteristics. The shareholders are on the board and, as with the Pathaks, they can use their judgment to give high-level performance incentives.

This unconventional package works. ABF has broadly kept pace with the share indices over the long term in spite of its largely mature, low-growth businesses. Sugar, for instance, is undergoing a costly upheaval because of changing EU farm policy. ABF’s achievement is much greater than it appears because most UK food producers have been a long-term disaster, especially those centred on commodity items such as bread or milk.

Most ABF profits are ploughed back into the business, so this is not an income stock, and the company has been financially conservative, avoiding crises.

During the share boom of the late 1990s ABF shares were so far out of fashion that the peak of the dot-com bubble was a great time to buy them. Over the past three years, however, the stock has become surprisingly fashionable and now trades at 17 times likely earnings this year – three points above the market average.

The reason is Primark: a bright but risky idea that ABF backed and has turned out a huge winner. Being a bargain basement yet fashionable is a rare combination, but the discount fashion chain has managed to combine the concepts and is expanding fast. In the 24 weeks to March 3 it contributed £91 million, or a third, of operating profits, and margins should improve as the latest stores pay back start-up costs.

Primark is an entrepreneurial success that makes the shares hard to value and could eventually become the cuckoo in the nest and be sold. But this is a problem that the family and outside investors can live with. Perhaps ABF’s latest move, into ethanol production, is more its style.

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