Colour coded boards and equipment are a cross contamination control. The colours are an industry convention rather than a legal requirement, but the convention is near universal in GB kitchens, and an inspector who sees raw chicken on the board used for salad will draw a conclusion about the whole system.
The usual colours
Red for raw meat, blue for raw fish, yellow for cooked meat, green for salad and fruit, brown for vegetables, and white for bakery and dairy. Some kitchens use purple for allergen free preparation, which is an increasingly common addition rather than part of the original set.
Why colour rather than washing
Washing between tasks works only if it happens every time and works every time. Colour removes the decision: the board for raw chicken is never the board for lettuce, so a busy service cannot get it wrong by forgetting.
Boards, knives and everything else
The system is worth extending to knives, tongs, cloths and storage containers, because the board is rarely the only thing that touches both. Colour coded cleaning cloths are one of the cheapest improvements a small kitchen can make.
Looking after them
Deeply scored boards hold bacteria in the cuts and should be replaced rather than scrubbed harder. Boards are also a structure and equipment item at inspection, so worn ones cost twice: once in the hygiene score and once in the confidence an officer has in the rest of the kitchen.
Questions people ask about chopping board colour code
What is a blue chopping board used for?
Raw fish, in the standard GB colour code.
What colour chopping board is used for vegetables?
Brown is the convention for vegetables, with green for salad and fruit. Some kitchens simplify to green for both.
Is the colour code a legal requirement?
No. It is an industry convention adopted because it works, and inspectors expect to see some reliable system for separating raw and ready to eat preparation.