In the UK I can currently buy an 800g loaf of bread for 45p (£0.45), a 500g tub of soft spread butter substitute for 99p (£0.99), and a 200g pack of 10 cheese slices for 65p (£0.65).

Each sandwich would cost about 12p (£0.12) to make, excluding the energy costs.

Doubling up on the cheese, or using higher quality cheese would still keep it under 20p per sandwich, and that’s off the shelf costs, no bulk discounts.

Excuse me while I write up a business plan…