>>512769437 (OP)The milk that comes off of free ranging cows in the spring in northern england and ireland is yellow from high beta-carotene content.
When cheddar was first popularized, the spring milk cheddar was most valuable because of the nutritional content.
When the brits switched from grazing to year round feedlots, they began adding annatto to the chese to simulate spring milk. This became so entrenched that it became legally codified.
The brits have a longstanding reputation for adulterating food, especially in the eduardian era.
Still to this day, i fucking despise british food. remember mad cow?