Food business must provide information to customers who need to avoid certain ingredients because of an allergy.
The law applies to all food businesses. Individuals who are not food businesses, but occasionally provide for at charity events or voluntary cake sales, for example, do not need to follow these requirements by law, but it would be good practice.
For further detailed advice and guidance, please follow the link to the Food Standards Agency. A useful leaflet entitled Allergen Information for loose foods is also available from this site.