What's the limit? Maybe we should tax couches, lest we become potatoes on them. Perhaps furniture in general should be banned, because we'd get ever so much more exercise lumbering up from the floor.

 

As tools of manipulation, sin taxes only work when astronomically high; having to take out a home equity loan for a packet of fags has undoubtedly discouraged smoking. But levying Wald's penny per tenth of a gram of salt and per gram of saturated fat on a Big Mac would raise the price from £2.49 to £2.88. Is 38p a sufficient deterrent? 

The lecturer's reasoning runs that if you make healthy food cheaper than the unhealthy kind, people will prefer the more beneficial choice. Really? This shibboleth that healthy food is more expensive than junk is a myth. I cook every night from scratch, and my homemade rosemary chicken thighs are cheaper than either a ready meal or KFC. Busy consumers buy prepared food and takeaways, not because making their own spaghetti Bolognese is too expensive, but because it's easier. They don't have to buy multiple ingredients, chop and sauté, or scrub any pans. Also, many an inexperienced cook can spend hours in the kitchen and produce the roundly inedible. Thanks to uniform standards, chain fast food is reliably tasty, and if it's greasy to boot that's why it's tasty. Costlier junk food is still effortless, still nefariously toothsome.

 

The ultimate hypocrisy of the sin tax is that on the one hand it's meant to reduce oreliminate detrimental behaviour; on the other, it's touted as a windfall. This nastyingredients tax would ostensibly earn the Treasury £38 billion per year — a full third of the NHS budget. But a fat tax would only raise that much money if it didn't work. 

Poor diet is one of those anathemas to politicians: not subject to legislation. Even education programmes are impotent (people don't avoid vegetables out of ignorance; they don't want to eat vegetables). No law can impart the discipline to not eat a cupcake. Besides, bloody hell! Any tax that would target Marmite, kippers, marmalade and Christmas pudding is a tax on being British.