I avoided tax yesterday, and bought the chocolate bar on the right.

Chocolate bars sold to eat: 20% VAT
Chocolate bars sold for cooking: 0% VAT

Even if exactly the same chocolate.

VFOOD6180 - Excepted items: Confectionery: The bounds of confectionery, sweets, chocolates, chocolate biscuits, cakes and biscuits: The borderline between confectionery and zero-rated food - HMRC internal manual - GOV.UK

@danneidle The real travesty of this is that the best chocolate for cooking with is halfway between milk and dark and sold in France as patisserie chocolate, whereas in the UK you have to buy Bournville and pay the VAT.