The 2026 Guide to Airport Security: What's Actually Banned and What's Just Discouraged

The jar of peanut butter was 340 g. The passenger had it in a clear plastic bag alongside a miniature of gin, a tube of toothpaste and what appeared to be sunscreen. The peanut butter was confiscated. The passenger was genuinely baffled — they had brought it on dozens of flights before. The screener had every right to take it, because peanut butter is classified as a paste and therefore falls under the liquid rule. The passenger's previous luck simply meant nobody had noticed until now.

Airport security rules in the UK and most of Europe have not fundamentally changed since 2006, when a foiled plot to smuggle liquid explosive components aboard transatlantic flights triggered the 100 ml restriction that now governs every hand-luggage check. What has changed is enforcement rigour, scanner technology, and the public understanding of what the rules actually mean. The gap between those three things produces the confiscations, the delays, and the confused passengers who leave perfectly legal items at the bin because they assumed they were banned.

This guide covers what is genuinely prohibited, what is commonly misunderstood, and what the screeners are actually looking for when your bag goes through the X-ray.

What airport security is actually checking for

The primary threat model for aviation security is the improvised explosive device — specifically, devices assembled or triggered on board, or hidden within luggage checked into the hold. The secondary concern is bladed or blunt-force weapons capable of being used to overpower crew. Everything in the security process follows from those two priorities.

Screeners at UK airports are trained to look for density anomalies on X-ray that suggest metallic or explosive material, for items shaped like known threat objects, and for liquids in quantities that could serve as an explosive precursor. They are not looking for nail scissors, forgotten sandwiches, or the battery pack you buried at the bottom of your bag — even though all three of those will slow the queue if they require a secondary check.

The 100 ml liquid rule — in full

The rule is often described as “liquids under 100 ml”, but the actual restriction is more specific: each container must hold no more than 100 ml (even if it only contains 10 ml of product), all containers must fit into a single transparent, resealable bag of no more than one litre capacity, and each passenger is limited to one such bag. At most UK airports, that bag must be removed from your hand luggage and placed separately in the tray.

The definition of “liquid” for security purposes is broader than the everyday sense of the word. It includes:

• Water, juice, soft drinks and any liquid that pours freely
• Gels — hair gel, aloe vera gel, lubricants
• Pastes — toothpaste, Marmite, hummus, peanut butter, Nutella, pâté
• Creams and lotions — moisturiser, sunscreen, foundation
• Aerosols — deodorant, hairspray, dry shampoo
• Liquid-solid hybrids — mascara, lip gloss, concealer sticks with a soft consistency

The practical implication: a 250 g jar of peanut butter is confiscated. A 100 ml pouch of the same product, purchased in that format, is permitted. A hard block of Parmesan is a solid and passes freely. A container of cream cheese does not. If you can squeeze, spread or pour it, assume it counts.

Exceptions to the liquid rule

There are three established exceptions. Baby food and breast milk in amounts required for the journey are permitted without restriction, and the passenger travelling with an infant does not need a baby present to carry them (though screeners may ask). Prescription medicines and medical liquid supplements are permitted in amounts required for the journey, provided they are accompanied by supporting documentation — a dispensing label in your name is usually sufficient. Duty-free liquids purchased airside and sealed in a security-approved tamper-evident bag are permitted, provided the bag is not opened before the next security point (which matters on connecting flights through a non-EU country with its own security check).

Items that are definitely banned in hand luggage

The following are prohibited in hand luggage at all UK airports, with no exceptions for quantity or packaging:

• Firearms and realistic imitation firearms — including starting pistols, replica weapons and anything that could be mistaken for a real gun.
• Explosive and incendiary substances — fireworks, flares, signal rockets, explosive cartridges.
• Stun guns, Tasers and electric shock devices.
• Sharp objects with blades over 6 cm — this covers most knives, box cutters, and bladed multi-tools. The 6 cm threshold applies to the blade length, not the overall length of the item.
• Sporting equipment that functions as a bludgeon — baseball bats, cricket bats, golf clubs, hockey sticks, martial arts equipment.
• Tools that can be used as weapons — axes, hatchets, drills (corded or battery), saws, crowbars, bolt cutters.
• Flammable liquids above the liquid allowance — lighter fuel in quantities above 100 ml, paint stripper, solvents.

These are hard rules, not suggestions. Unlike a borderline liquid that might clear on one screener's discretion and not another's, the above items will be refused regardless of how they're packaged, declared or explained.

Items people commonly think are banned but aren't

A significant number of items are left at the security bin because passengers assume, wrongly, that they are prohibited. The most common:

• Nail clippers — permitted. They have a small filed edge, not a blade, and are not classified as a bladed article.
• Knitting needles and crochet hooks — permitted at all UK airports and most European ones. The guidance changed years ago; many passengers are operating on a mental model from the early 2000s.
• Scissors with blades under 6 cm — technically permitted. However, screeners sometimes confiscate them anyway under discretion, particularly if the blades appear pointed rather than rounded. Keep them in your liquids bag for visibility.
• A single disposable lighter or one standard cigarette lighter — one per person is permitted in hand luggage. Lighter fluid refills are not.
• Over-the-counter medication in solid form — paracetamol, ibuprofen, antihistamines. Only liquid medications need to follow the 100 ml rule.
• Food in solid form — sandwiches, fruit, hard cheeses, crackers, nuts, chocolate. These go in your bag as normal. It is only the liquid, gel and paste versions of food that fall under the restriction.
• Portable chargers and power banks — permitted in hand luggage. They must not go in checked baggage because of lithium fire risk. Most airlines have a capacity limit (typically 100 Wh, or around 27,000 mAh).

Electronics: what to take out and what to leave in

Standard UK and European airport security requires laptops to be removed from their cases and placed separately in a tray. Tablets, e-readers and phones generally do not need to be removed, but the guidance varies by airport and by the technology in use — some newer scanner installations handle electronics in bags without issue. When in doubt, take the laptop out; it is faster to put it back than to be pulled for a secondary bag check.

Cables, adaptors and battery packs create X-ray clutter. Rolling cables into coils or using a cable organiser reduces the chance of your bag needing a manual check. A large knot of USB cables around a power bank looks, on an X-ray screen, like something worth a second look.

Our guide to travelling with a laptop covers the additional customs and export-control considerations for high-performance machines in more depth.

Checked baggage: the different rules

Items that are banned in hand luggage are often permitted in the hold. Sharp objects — kitchen knives, a set of steak knives, scissors of any length — are fine in checked baggage. Tools are fine. Sporting equipment is fine. The logic is that access to the hold is not possible during flight.

The checked-baggage prohibitions concern items that pose a risk to the aircraft itself:

• Lithium-ion batteries above 160 Wh (spare batteries must travel in hand luggage)
• Power banks of any capacity — must be in hand luggage
• Flammable liquids above airline-specific thresholds (paint, solvents, lighter fuel)
• Pressurised containers exceeding airline limits (full scuba tanks, CO₂ cartridges above a certain size)
• Fireworks, explosives, and flares — prohibited everywhere, hold or cabin

The power bank rule catches people consistently. A passenger who packs their portable charger into a checked suitcase to save space in their hand luggage will have it removed at check-in, or will face a delayed departure if it is found by hold-baggage screening. Pack power banks in your carry-on bag before you reach the check-in desk.

What happens when your bag is flagged

A bag flagged for secondary screening is pulled from the belt and inspected manually by a screener. They will look at the X-ray image and then open the bag to check the item of concern. The process typically takes two to five minutes. The outcome is either clearance (the item is fine, off you go), confiscation (the item is prohibited and goes in the bin), or — at some airports — the option to go back and check the item into the hold. Not all airports offer the third option; Heathrow's main terminals generally do, many regional airports do not.

Arguing with a screener does not change the outcome. Screeners have discretion on borderline calls, and the discretion runs in one direction — they can clear an item, but once a decision to confiscate has been made, it is final. The only effective response to a confiscation is to check the rules before packing next time.

Getting through faster

The security queue moves at the speed of its slowest passenger. A few straightforward habits make a meaningful difference:

• Prepare in the queue, not at the belt. Empty your pockets, untie your shoes and unzip the top of your bag while you're standing in line. The belt should be the moment of transfer, not the moment of searching.
• Put your liquids bag at the top of your carry-on before you arrive at the airport. If the bag needs to come out, it should come out in one move.
• Wear shoes with slip-on access. At most UK airports shoes do not need to be removed, but metal buckles and thick soles can trigger an additional scan. Low-metal footwear moves faster.
• Use a compact liquids kit. Ten tiny bottles in one clear bag take less time to scan than three large bags and a cosmetics case. The packing tool can help you plan hand-luggage contents before you pack at home.
• Know what relaxed-screening lanes look like. Several UK airports now have next-generation CT scanner lanes where laptops and liquids remain in the bag. If your airport has them and you qualify for the lane, use it — it's meaningfully faster.

The gate security check

An increasing number of UK and European routes involve a second security check at the gate — particularly for US-bound flights, some Middle Eastern routes, and certain charter departures. This check focuses on identity verification and occasionally involves rescan of hand luggage. Items that made it through the main security hall are not automatically cleared for the gate check; the same rules apply.

If you are on a route that historically includes a gate check and you purchased a sealed bottle of water airside, note that gate security at some airports will confiscate it rather than allow it through — the tamper-evident exception that applies at the main check does not always carry to the gate. It is a minor frustration and an entirely avoidable one.