In 1970 the architectural critic Peter Reyner Banham wrote a celebrated New Society essay called "The Crisp at the Crossroads". A champion of the serious study of consumer ephemera, Banham gave the humble crisp the sort of attention his colleagues reserved for buildings by Le Corbusier. His theme was the transformation of the crisp from marginal pub fodder into mass-marketed, multi-flavoured snack.
Now the crisp is at another crossroads. In one direction we see the long-term decline of the bog-standard crisp. Golden Wonder has gone bust and had to be rescued by the Northern Irish firm Tayto. Crisps will soon be banned from school vending machines in the latest instance of the Jamie Oliver effect. Gary Lineker is back as the nice guy in adverts, telling us about the reduction of salt and saturated fat in Walkers crisps. In another direction, we see the rise of "premium" crisps such as Walkers Sensations, Burts and Kettle Chips.
The history of the crisp is, as Kingsley Amis's Lucky Jim might have written, a strangely neglected topic. According to Banham, before the 1960s the crisp had the same purpose as a Babycham: respectable women could ask for a bag of crisps instead of a beer in a pub, thus remaining ladylike without dropping out of a round.
Then Golden Wonder became more market-savvy and ended the 40-year dominance of Smith's Crisps. Golden Wonder introduced ready-salted crisps in direct competition to Smith's, whose packets had little blue twists of greaseproof paper full of salt. This led to the "flavour wars", with Smith's and Golden Wonder battling to produce new varieties such as cheese and onion, salt and vinegar and smoky bacon.
In the year Banham wrote his essay, Golden Wonder invented the Cheesy Wotsit, thus paving the way for what the industry calls "mimics": crisps made of powdered potato, maize or starch, re-formed into shapes such as hoops, monsters or Space Invaders. Some were aerated, so eating them didn't seem to fill you up. The high percentage of air in any bag led to the belief that they were unfattening, which has since been exposed as a myth.
As Banham pointed out, crisps are a non-food, with little nutritional value, so eating them has to be a theatrical, symbolic act. The posh crisps, which are now so popular, have this "audio-masticatory" appeal in spades. They are solid and crunchy. Eating them is hard work; they do not melt in the mouth like Quavers or Ringos. Their bags have minimalist designs with restrained colours, and they seem pleasingly crackly.
Posh crisps are ironic. The small firm Jonathan Crisp markets its product as "crisps for snobs" and "the very essence of civility". Don't be fooled by the self-mockery; posh crisps carefully target middle-class food obsessions. First, they make a fetish of being "hand-cooked". Burts even has the fryer's name and photograph on its packets. Second, they have more exotic ingredients, although much of this is down to adding adjectives - instead of "salt and vinegar" you have "sea salt and malt vinegar", and instead of "cheese and onion" you have "mature Cheddar and red onion".
Of course, "posh crisp" is an oxymoron. While the truly posh eat canapés, the rest of us make do with slices of potato cooked in their skins, which their makers have the cheek to call aspirational.
On its now outdated website, Golden Wonder snipes at the posh crisp: "We don't want to make nouvelle cuisine. We just want to make crisps. Good, honest, delicious crisps at that. After all, that's exactly what the British public fell in love with and why they stick with us." Except they didn't, the snobs.
Joe Moran is writing a book on daily life for Profile