The Food Labelling Regulations 1996

4.  All amounts given—

(a) are to be per hundred grams or hundred millilitres of the food, as is appropriate, and, where it is wished to do so, those in either—

(i) a quantified serving of the food, or

(ii) provided that the total number of portions contained in that sales unit of the food is stated, in one such portion of the food,

(b) shall be such amounts as are contained in the food as sold to the ultimate consumer or to a catering establishment save that, where sufficiently detailed instructions are given for the preparation for consumption of the food, they may (if expressly said to be so) be such amounts as are contained in the food after the completion of such preparation in accordance with the said instructions, and

(c) shall be averages based, either alone or in any combination, on—

(i) the manufacturer’s analysis of the food,

(ii) a calculation from the actual average values of the ingredients used in the preparation of the food,

(iii) a calculation from generally established and accepted data,

and “averages” for the purposes of this sub-paragraph means the figures which best represent the respective amounts of the nutrients which a given food contains, there having been taken into account seasonal variability, patterns of consumption and any other factor which may cause the actual amount to vary.