Green - salt & vinegar
Blue - cheese & onion

Blue cheese and onion and green salt and vinegar.
It was the other way round years ago, maybe was a different brand.

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As long as I can remember Its always been - Blue - salt and vinegar, Green - cheese and onion... Walkers changed it round as a marketing ploy in the 80's/90's to stand out which obviously worked ... but i still don't rate 'em...

Green - cheese n onion
Light blue - salt n vinegar

In Australia Salt and Vinegar is pink and cheese and onion is yellow :omgno:

Red is original flavor?

I usually see onion associated with the green color in the snack industry, so Cheese & Onion is therefore green and Salt & Vinegar is blue.