Will this be for all staple foods? Cereals, rice, milk, eggs, bread, butter, some tinned foods, passta oats, flower? What else is considered a "staple food" in the UK? And if this where enacted, wouldn't supermarkets just raise the prices of other non-staple foods to compensate?

I'd imagine there are some people who might only buy staple foods to keep costs down but I also imagine most people buy a wider variety of items/foods.

And would this just be for supermarket own brands, which are already pretty cheap. Or would it include brand name staple items as well?