Any place in Britain that sells you food it has cooked or assembled must tell you, accurately, whether it contains any of fourteen named allergens. It can do that in speech or in writing, but if it does it in speech there has to be a visible sign telling you to ask.
That single rule is the whole legal framework, and it covers restaurants, pubs, cafés, bakeries, market stalls, coffee counters, takeaways and delivery apps. It applies to a plate of pasta and to a flat white. Nothing else about ingredients has to be volunteered to you at all.
Our guide to eating as a vegetarian in Britain deals with the ingredients that hide for reasons of preference. This page deals with the ones that can put a person in hospital: what the kitchen owes you, what wording gets a real answer out of it, and where the system is thinnest.
What a British kitchen must do
- Tell you about
- The fourteen allergens listed in food law, if they are deliberately in the dish
- Method
- Written or spoken. If spoken, a notice must point you to it
- Packaged on site
- Full ingredient list on the label, allergens made to stand out
- Ordered online
- Allergen details free of charge, in writing, before you pay and again on delivery
- Not required
- "May contain" warnings, cross-contamination detail, nutrition advice
- Regulator
- Food Standards Agency, enforced by each London borough's environmental health team
The fourteen, and the four that catch visitors out
The list is fixed in law and is the same in England, in Wales and in Northern Ireland. In alphabetical order: celery; cereals containing gluten; crustaceans; eggs; fish; lupin; milk; molluscs; mustard; peanuts; sesame; soybeans; sulphur dioxide and sulphites above ten parts per million; and tree nuts.
Four of those routinely surprise people from other countries.
- Celery. Not on many national lists, and it is everywhere in British cooking: stock cubes, soup bases, gravy, stews, stuffing. If you react to celery, Britain is the country where you have to ask the most often.
- Mustard. Also unusual as a named allergen elsewhere. It turns up in salad dressing, mayonnaise, sausages, cheese sauce and almost every piece of British charcuterie.
- Sulphites. Declared only above ten parts per million, which brings in most wine, a lot of dried fruit and some soft drinks and vinegars. This is the one people forget to ask about at a bar.
- Lupin. Rare in Britain but legally listed, because lupin flour appears in some imported pastry and gluten-free baking.
Note what is not on the list. Coconut, kiwi, banana and garlic are not regulated allergens, so nobody has to mention them. Peanuts and tree nuts are two separate entries, and a kitchen that has checked one has not necessarily checked the other.
Written, spoken, or both: what changed in 2025
For years the rule was simply that the information had to reach you somehow. A pub could train its staff, put a small line at the bottom of the menu saying to ask, and comply fully. Plenty still do.
In 2025 the Food Standards Agency published best-practice guidance that goes further. It tells businesses serving loose food that what consumers actually want is the information on paper and then confirmed in conversation — the guidance says allergen details should be "easily available in writing and be underpinned with a conversation". It also asks staff to raise the subject first, with a line such as "Do you have any allergen requirements?"
Guidance is not law, so you will meet both systems in the same street. What it means in practice is that a growing number of London restaurants now hand over a separate allergen menu, or a tablet, or a folder at the till. Ask for it by name: "Do you have an allergen menu?" is understood everywhere and gets you the document rather than a guess.
Nothing printed on the packet is not the same as nothing in the packet. Precautionary wording such as "may contain" is voluntary here, and food law does not oblige anyone to print it. A packet without that warning has not been tested and cleared; it has simply not been labelled. Judge a packet by its ingredients, and judge a kitchen by what it tells you about its fryers and its surfaces.
The sandwich in the chiller cabinet is a different rule
Since October 2021 anything a business packages on its own premises before you choose it has needed a full label: the name of the food, every ingredient, and the allergens picked out of that list in bold, capitals, a different colour or underlining. The change is usually called Natasha's Law.
This is the rule that makes British café chillers genuinely easy to shop from. A wrapped sandwich, a boxed salad, a pie in film, a soup already in its pot, a cake under cling film: all labelled. For what the separate "gluten-free" claim on those packets means, see eating gluten-free in the city.
What is not labelled, and does not have to be: a cake sitting uncovered on a stand, an open salad bar, the bread brought to your table, anything made after you order it, and your coffee. Those are loose food and fall back under the ask-and-be-told rule.
Wording that gets a useful answer
The single most important word is allergy. British kitchens run a different procedure for an allergy than for a dislike: a different chopping board, a separate pan, a check of the supplier list, sometimes a manager coming to the table. Say it plainly and say it before anyone writes anything down.
Four sentences that work:
- "I have a severe allergy to sesame. Would you ask the kitchen before I order?"
- "Do you have the allergen information in writing?"
- "Does the fryer get used for anything with wheat in it?"
- "Can the kitchen make this without the dressing, or is the dressing already on it?"
Two answers to distrust. "It should be fine" is a guess rather than information; ask them to check. "We can't guarantee anything" is honest, and it means the kitchen knows its own limits — take it seriously rather than pushing, and eat somewhere else. Guidance is explicit that staff should be able to explain what precautions they can and cannot take.
If you are not confident speaking English, write the allergen on your phone in English and show the screen. The names in the list above are the exact words British staff are trained on, which is why a written note beats a paraphrase. Our glossary of British food words covers the rest of the menu.
Ordering through an app, or by phone
Delivery and collection orders are covered by a separate and stricter part of the same regulations. When food is sold at a distance, the allergen information must be available to you free of charge and in writing, both before you place the order and again when the food arrives.
In practice that means the allergen details should be on the listing page in the app, not hidden behind a phone call, and should come with the bag. If a restaurant's page in a delivery app has no allergen section at all, that is a red flag about the restaurant rather than about the app.
A free-text "no nuts please" box is not a legal instruction. Notes typed into a delivery app arrive as a request to the kitchen, not as a declared allergy, and busy kitchens treat them accordingly. If the reaction would be serious, telephone the restaurant directly or eat in, where you can say the word allergy to a person who is looking at you.
Where the system gets thin
The law is the same everywhere; the ability to comply with it is not. Five situations to approach differently.
| Setting | What to expect | What to do |
|---|---|---|
| Street-food stall | One or two people cooking in a small space, shared utensils, no printed matter | Ask before the queue builds; go at a quiet hour |
| Very small independent restaurant | Excellent knowledge, sometimes poor English, no written document | Ask for the owner or chef; accept a spoken answer from them |
| Buffet, carvery or salad bar | Shared tongs and dripping between trays | Ask for a portion plated from the kitchen instead |
| Bar and pub garden | Sulphites in wine and cider; snacks decanted from bulk bags | Ask to see the original packaging |
| Festival or pop-up | Temporary traders, borrowed equipment | Eat something simple and single-ingredient, or eat beforehand |
Markets are the interesting case. The traders at Borough Market and the other big London food markets are regulated businesses and most handle the question well, but you are asking someone who is also taking cash and turning a grill. A guided food tour is worth considering if you want to taste widely with a fixed allergy, because the guide can brief every stop before you arrive.
At the other end, the large pub and restaurant chains are the most systematic operators in the country on this: allergen matrices online, filters on the menu, trained duty managers. Our guide to Britain's restaurant chains explains who owns what.
Cuisines where the risk sits somewhere unexpected
Allergen risk in London is not distributed the way visitors assume. A few patterns worth knowing:
- Fish stock in dishes that look vegetarian. Dried bonito is the base of a great many Japanese broths; our guide to Japanese food in London goes into which. Thai and Vietnamese cooking uses fish sauce in the same invisible way.
- Sesame in bread. Not only on the crust. Tahini goes into Middle Eastern sauces, and sesame oil finishes a lot of East Asian dishes.
- Nuts in British desserts and Indian sweets. Ground almond is a standard ingredient in both, and it is not visible.
- Milk in unexpected savoury places. Butter under a steak, milk powder in a batter, cheese in a stock.
- Walk-in restaurants at their busiest. If you are eating somewhere that does not take bookings, arrive at the start of service rather than in the rush, when there is time to check.
If a reaction starts
For a mild reaction, a pharmacy is the fastest help in London and needs no appointment: see what a London pharmacist can deal with. If you are unsure how bad it is, ring 111 for NHS advice — the call is free and the line answers at any hour.
For anaphylaxis, the NHS instruction is to use an adrenaline auto-injector straight away if one is available and to call 999 at the same time, saying that you think it is an anaphylactic reaction. Lie down with your legs raised; if breathing is hard, sit up slowly instead. The NHS is explicit that you should not stand or walk at any point, even if you start to feel better, and that a second auto-injector should be used after five minutes if symptoms have not improved.
Accident and emergency treatment is given to everyone in England regardless of where they live, but care after you are admitted as an inpatient may be charged to overseas visitors. The money side is set out on our pages about using the NHS as a visitor, insurance cover for a UK trip and which number to ring in an emergency. Read them while you are still planning, not from a waiting room.
If a restaurant gave you wrong information, that is a matter for the borough's environmental health team rather than for the restaurant alone. Our page on complaining in Britain explains how to report it, and the Food Standards Agency's hygiene rating search shows which authority covers a given address.
Asking is completely ordinary here, and it will not cost you the table. British front-of-house staff field allergy questions every service and are trained to. Nobody will treat it as a fuss, an imposition or a reason to seat you late, and it is far more normal to ask at the door than to work it out from the menu. The same is true at a bar: see our page on the Bermondsey taprooms for how small venues without kitchens handle it.
Frequently asked questions
Does a London restaurant have to tell me about allergens by law?
Yes. Any business selling food that is not prepacked must make the presence of the fourteen regulated allergens known to you accurately. It may do so verbally, but if it does there has to be a clearly displayed notice telling customers where to ask. Refusing to answer, or guessing, is not lawful.
Is allergen information in British restaurants always written down?
Not always. Written information is best practice rather than a legal requirement for food made to order, and the Food Standards Agency began pressing for it in 2025. Many London restaurants now keep an allergen menu or folder, so ask for it directly rather than waiting for it to be offered.
What is Natasha's Law and does it affect me as a visitor?
It is the rule, in force since October 2021, that food packaged on the premises before a customer chooses it must be labelled with every ingredient, with the allergens made to stand out. It is why wrapped sandwiches, boxed salads and film-covered cakes in British cafés are labelled, which makes buying lunch on the move much easier.
Are coeliac disease and a wheat allergy treated the same in Britain?
Gluten-containing cereals sit on the list of fourteen, so both conditions are covered by the duty to tell you. "Gluten-free" as a claim on a menu or a packet is separately regulated and means the food meets a specified threshold, which is a different and stricter statement than simply leaving wheat off an ingredients list.
Can I bring my own food into a London restaurant because of an allergy?
There is no legal right to, and most restaurants will say no for their own food-safety reasons. A better approach is to telephone ahead, explain the allergy and ask what the kitchen can do. Places that cannot accommodate you will usually say so on the phone, which saves the journey.
Sources
- Food Standards Agency - Food allergy and intolerance advice for consumers (checked September 2026)
- Food Standards Agency - Allergen information for non-prepacked foods: best practice (checked September 2026)
- Food Standards Agency - PPDS allergen labelling for restaurants, cafés and pubs (checked September 2026)
- Food Standards Agency - Allergen labelling technical guidance, part 2: non-prepacked food (checked September 2026)
- NHS - Anaphylaxis (checked September 2026)
- NHS - Food allergy (checked September 2026)
- Food Standards Agency - Food hygiene ratings search (checked September 2026)