How do I read allergen labelling on UK food?

The 14 allergens, how they must be shown, what Natasha's Law changed, and the limits of what a label can tell you.

Difficulty: beginner
Time: 10 min
Read: 4 min
Safety: warning

Short answer

The 14 regulated allergens must be emphasised in the ingredients list, usually in bold. Read the ingredients, not the front of the pack, and read them every time — recipes change. 'May contain' statements are voluntary, so their absence does not mean an allergen is absent, only that the manufacturer chose not to declare a risk.

UK allergen law is genuinely useful and it is also frequently misread. It tells you what is deliberately in a product; it says much less about what might have got in by accident. Knowing exactly what the label covers, and what it does not, is what lets you use it properly.

Safety

Allergen labelling law covers 14 named allergens in the ingredients list. It does not require a warning about accidental cross-contamination, so the absence of a 'may contain' statement is not a guarantee of absence. For a severe allergy, check the ingredients every time — recipes change without notice — and contact the manufacturer if a product matters and the label is unclear.

Step by step

Learn the 14.Celery; cereals containing gluten (wheat, rye, barley, oats, spelt, kamut); crustaceans; eggs; fish; lupin; milk; molluscs; mustard; tree nuts; peanuts; sesame; soya; and sulphur dioxide and sulphites above 10mg per kilogram or litre. These are the ones the law requires to be declared and emphasised.
Read the ingredients list, not the front of the pack.Front-of-pack claims are marketing. The legal information is in the ingredients list, where any of the 14 must be emphasised — in the UK almost always in bold, sometimes in capitals or underlined. Scan for the bold.
Look for the allergen's real names.Milk appears as whey, casein, lactose, ghee. Egg appears as albumen and ovalbumin. Wheat may appear as semolina, durum, spelt or couscous. The law requires the allergen source to be named, so 'whey (milk)' is what you should see — but knowing the aliases helps you spot a mistake.
Understand what Natasha's Law changed.Since October 2021, food that is prepacked for direct sale — made and packed on the premises where it is sold, like a supermarket sandwich made in store or a bakery salad box — must carry a full ingredients list with the allergens emphasised. Before that it could be sold with no list at all.
Know what loose and non-prepacked food requires.Food sold loose — a restaurant meal, a bakery counter item, a takeaway — does not need a written ingredients list, but the business must be able to give you allergen information. It can be verbal, but they must have it and must give it accurately. Ask directly and specifically.
Treat 'may contain' as a real warning.Precautionary allergen labelling is voluntary and unregulated in wording, but a manufacturer that has put it on has identified a genuine cross-contamination risk in their process. For a severe allergy, avoid the product. It is not a legal disclaimer to be ignored.
Do not read the absence of a warning as an assurance.Because 'may contain' is voluntary, a product with no such statement may still be made on shared equipment. If a product matters, contact the manufacturer — most have an allergy line and will tell you about their process.
Check every time, including familiar products.Recipes and suppliers change without any change to the packaging design. The commonest way a careful person gets caught out is a product they have bought safely for two years.
Watch imported and online products.Food bought from abroad or through third-party online sellers may carry labelling to a different country's rules, in another language, or none at all. Treat those with much more caution.

Tips

Photograph the ingredients list of products you rely on. It gives you a reference and it makes it obvious when a recipe has changed.
The Food Standards Agency runs a free allergy alert service that emails product recalls and allergen labelling errors. It is worth subscribing to if someone in the house has a serious allergy.
Supermarket own-brand free-from ranges are made to controlled processes and are usually a safer starting point than working through mainstream products.
In a restaurant, ask about preparation as well as ingredients — shared fryers and shared grills are not covered by an ingredients answer.

Common mistakes

Relying on a 'free from' claim on the front of the pack — Front-of-pack claims are regulated for some terms and not others, and they only address the allergen they name. The ingredients list is the authoritative source and takes ten seconds to read.
Assuming the 14 allergens are a complete list of what people react to — They are the 14 the law requires to be declared, not the 14 that exist. Someone can be allergic to kiwi, banana, legumes or almost anything else, and those will not be emphasised — the full ingredients list still has to be read.

Questions people ask

What does 'may contain traces of nuts' actually mean?

It means the manufacturer has assessed their process and identified a real possibility of cross-contamination — shared lines, shared equipment, shared premises. The wording is voluntary and unstandardised, so 'may contain', 'not suitable for', and 'made in a factory that also handles' should all be treated as the same warning. For a severe allergy, avoid it.

Does a restaurant have to tell me about allergens?

Yes. Food businesses must provide accurate allergen information for the 14 regulated allergens for all the food they sell, including loose food. It can be given verbally provided there is a clear signposted way to ask. If staff cannot answer confidently, that is itself information — do not order it.