Shop for snacks: Buy potato chips at Amazon.com
Taste test: These are good ketchup chips. They've got a medium-strength ketchup flavor on the standard thin Walkers chips. Unlike many American and Canadian varieties of ketchup chips, they don't have red-colored flavor powder all over them; instead, there are just a few (very few) specks of red that you might not even notice. So now I'm figuring that all the red on those other chips is actually just for show.
Aroma: Mild ketchup/vinegar aroma.
Online store: Buy potato chips at Amazon.com
From the package: "Ingredients: Potatoes, vegetable oil, tomato ketchup flavour [flavouring, flavour enhancer (monosodium glutamate), lactose], salt." ... "Is there a £20 note inside?" (Nope.)
This snack was discovered by Jeremy in London.