Terry Prachett
© Kevin Nixon/SFX Magazine/Future/Getty ImagesTerry Prachett
Jack Monroe's use of the character Sam Vimes in a critique of cost-of-living statistics shows the enduring power of the author's fury and humour.

When the poverty campaigner and cookbook author Jack Monroe realised that the Office for National Statistics (ONS) was reporting a skewed and unfair version of the cost of living, they reached for Terry Pratchett, the brilliant author of comic fantasy whose books bristle with fury at the injustices of the world. Pratchett best expressed his anger through the character of Sam Vimes, the police chief who grew up on the breadline but, through a chain of unlikely events, finds himself among the monied elite, and one of the most powerful men in the city.*

In Men At Arms (1993), the second of Pratchett's novels to feature Vimes and the City Watch, the author gives his protagonist a searing monologue that he called the "Captain Sam Vimes Boots theory of socioeconomic unfairness". In full, it runs like this:
"Take boots, for example. He earned thirty-eight dollars a month plus allowances. A really good pair of leather boots cost fifty dollars. But an affordable pair of boots, which were sort of OK for a season or two and then leaked like hell when the cardboard gave out, cost about ten dollars. Those were the kind of boots Vimes always bought, and wore until the soles were so thin that he could tell where he was in Ankh-Morpork on a foggy night by the feel of the cobbles. But the thing was that good boots lasted for years and years. A man who could afford fifty dollars had a pair of boots that'd still be keeping his feet dry in ten years' time, while the poor man who could only afford cheap boots would have spent a hundred dollars on boots in the same time and would still have wet feet."
It's a devastating summary of the class divide that illustrates how the rich and the poor see and experience the world in completely different ways. That a shifting of a few pence, here or there, can make no difference to one person, while being enough to make another go hungry. That being poor is actually more expensive than being wealthy and, worse, traps you in a cycle of being poor.

It was with this inspiration that Monroe, a Pratchett fan, started to assemble what they are calling - with the full permission of the author's estate - the "Vimes Boots Index", a new food index that tracks the "insidiously creeping price" of the most basic food items. Monroe is well-placed to do so: they made their name publishing inventive recipes made on the smallest available budget, every ingredient costed - sometimes down to fractions of pence - even taking into account the electricity needed to cook the meal. They have been monitoring the true "cost of living" for over a decade - not the one the ONS espouses, based on the price of 700 pre-selected goods including (as Monroe wryly notes in their article in the Observer) "a leg of lamb, bedroom furniture, a television and champagne", but the ones familiar to those who have no choice but to spend the absolute minimum: value ranges, budget items and absolute basics. The ONS bases its statistics on average prices, but for millions of the country's poorest, average prices don't reflect reality at all.

Rhianna Pratchett, Terry's daughter, said that the author - who died in 2015 - would be extremely proud that his work was being used in this way. The way in which Monroe is approaching and questioning the ONS data gets to the very heart of Pratchett's writing. Sometimes dismissed - to his eternal annoyance - as a mere peddler of funny books about wizards, Pratchett was an expert in humanity who used his absurd universe of trolls, dwarfs, witches and giant space turtles to thoroughly examine and artfully skewer the world in which he was writing.

Pratchett understood human psychology, sociology and economics as well as any author since Dickens, and was angrier and funnier about it than most of them. He was also supernaturally well-read. The "Vimes Boots Theory" is an elegant distillation of an old economic and philosophical concept famously explored by Robert Tressel in his classic 1914 book The Ragged Trousered Philanthropist. Pratchett, a voracious reader who devoured Victorian satire, physics textbooks and fairy stories at the same rate, would likely have discovered the book in his local library in Beaconsfield, Buckinghamshire.

Some of Pratchett's best writing is about social inequality - not just that it exists (although he was pretty bloody livid about that) but why it exists and how it's perpetuated. In 2009's Unseen Academicals Pratchett talks about "crab buckets", likening society to crabs sold for the pot, which "you can keep in a bucket without a lid" because "any that tries to get out gets pulled back" by the other crabs - a neat analogy for a self-perpetuating class divide. In Interesting Times (1994), citizens of an enslaved society are kept in place by "something worse than whips" - they're taught to keep themselves in place. Making Money (2007) eviscerates the absurd house of cards that is high finance and banking about a year before the 2008 financial crash, never losing sight of the link between the movement of money and the lives of ordinary people.

Pratchett himself, like Sam Vimes, ended his life a fabulously wealthy knight of the realm with invitations to all the best parties. But, also like Vimes, he began at the bottom - a working-class lad with an innate understanding of people who was clever enough and lucky enough to climb out of the crab bucket. Neither he nor his protagonist ever lost sight of that journey, or the forces in place that prevented most people from taking it. In that sense, Jack Monroe's new index, designed to recognise and address the same forces of inequality, is absolutely worthy of the name "Vimes".

*There is about three novels' worth of backstory, and we just don't have the time, alright? Read Guards! Guards!, Men At Arms and Feet of Clay, and come back to me. And then, well, read the others. They're great.