The sin tax on sugar has worked, not by getting consumers to stop buying the stuff, but by getting the vendors to change their recipes to avoid the tax.

The sugar tax in the UK is ONLY on fizzy drinks. And people are price sensitive when buying carbonated drinks. If one brand is 15p cheaper than another, that is what people will buy.

So pretty much all the drinks manufacturers reduced their sugar so that their drink wouldn't be taxed. The only exception being Coca Cola Classic which has a specific recipe that can't be changed.