They were separate but equal. In hindsight – although it was neither intended that way nor obvious at the time – it is clear that it was their very segregation that guaranteed equality. Rainbowism, discredited and spurned elsewhere, triumphed. And, in a turn that really should have surprised nobody with even a cursory understanding of history, it was the blacks who suffered.

But well enough could not be left alone. The colour walls were broken down.

The injustice was all too evident. The solution was inadequate. “Look,” they said, “we have created a specially demarcated zone for just the blacks.”

What they failed to say was that the blacks would go straight to the back of the shelf.

As is so often the case, the roots of the problem stretch all the way back to the trickery of colonial-era Britain.

Somewhere around 1909 Charles Gordon Maynard came up with an innovation on the age-old recipe of adding a gelling agent to fermented wine, and used fruit juice instead – but would still call the product “wine gums”.

It was a plan hard to sell to his father Charles Riley Maynard, records author Paul Chrystal in his bookConfectionery in Yorkshire through Time. After nearly 30 years in the sweet trade Charles Riley had a keen eye for what would sell, but he was a strict Methodist and teetotaller. Only once convinced that the “wine” part of the name was nothing but (rather deceptive) marketing did he agree to try out the product.

By the late 20th century Maynards wine gums were vastly popular throughout the British Commonwealth. Today it regularly tops lists such as “The Ten Best Sweets” compiled by idle bloggers and “What I Like About England” compiled by idle American tourists.

They were, and for the time being remain, equally popular in South Africa. Sweet brand Beacon bought the rights to manufacture wine gums in 1949 and started to manufacture them in Durban. Beacon, in turn, was folded into listed food giant Tiger Brands.

For those of a modernist or rainbowist disposition, wine gums are available in loose packs in which each flavour has a unique shape: kidney, crown, diamond, circle and rectangle. The different sizes and shapes have an adverse effect on the flavour profile, however, and for purists there is only one presentation of wine gum: 15 thick-sliced disks of small diameter.

For decades these round packs shunned the shameless mixing that took place in other versions. The different flavours were arranged in groups of three, always, depending on the pack orientation: three red, three yellow, three black, three orange and three green. Never more, never less.

The arrangement was a logistical one: the previous generation of machines that extrude and slice and pack deal better with groups of sweets than single ones. But the consequences included a range of rituals and habits built around the arrangement, much of that centred around the black gums, nominally flavoured blackcurrant.

“Reds and blacks are the joint favourite flavours,” the English manufacturer of wine gums Cadbury tells us. “They account for 80% of people’s preferred favourite choices.”

Red, on the outside of the roll, suffered the curse of being accessible. Black required strategy. Eat from each side of the roll equally until you reach the middle, or first eat one side then the other? Offer the roll to friends and family early in proceedings, so they deal with the less-loved colours? What if they reach right into the middle and claim the black? And if on the receiving end of such an offer, is it acceptable to claim one of the three black gums?

This June the manufacturers put all such concerns to bed. Suddenly packs of round wine gums were randomised, with each colour indiscriminately laid next to another. Only rarely were two of the same colour neighbours, and, in hundreds of examined cases, no arrangement of three-of-a-colour could be found.

Investigations this week confirmed that almost none of the packs contained three black gums. The average was closer to 1.5 and, horrifically, some contained no black at all.

Having quietly starved consumers of black wine gums, Tiger Brands then introduced “black only”: packs of wine gums consisting only of the nominally blackcurrant flavour.

In the chaos that followed the realignment, however, the “black only” packs were almost impossible to find. Retailers reported that they were not aware of the product, or did not have the extra shelf space to accommodate it. Several showed both ignorance about the different colours and a cavalier attitude towards the matter.

Tiger Brands did not immediately respond to questions on the matter, including whether the marginalisation of black was a mercenary move, and whether there had been a political motivation behind its adoption of rainbowism.