What Can't You Post With Royal Mail? A Guide to Prohibited and Restricted Items

Every UK courier, Royal Mail included, maintains a list of items that can't be sent at all and a separate list of items that can be sent only under specific conditions — packaging requirements, quantity limits, or declared-content rules. This guide covers the broad categories worth knowing, but because exact rules change and carry real legal and safety consequences, always check Royal Mail's current official prohibited and restricted items list before shipping anything that might fall into a grey area.

Why this distinction matters

"Prohibited" means an item cannot be sent through the network under any circumstances — no packaging or declaration makes it acceptable. "Restricted" means an item can be sent, but only if specific conditions are met — particular packaging, a maximum quantity, or additional documentation. Treating a restricted item as if it were simply allowed, without meeting its conditions, is one of the more common ways sellers run into trouble without realising it.

Dangerous and hazardous goods

Flammable, explosive, corrosive and other hazardous materials are generally prohibited outright through standard postal services, covering everything from certain aerosols and flammable liquids to fireworks and corrosive chemicals. Some items in this category that seem innocuous — certain cosmetics, cleaning products or DIY materials — can fall under hazardous goods rules due to their specific chemical contents, so it's worth checking product-specific guidance rather than assuming a household item is automatically fine.

Batteries

Batteries, particularly lithium batteries, are a commonly restricted rather than fully prohibited category — loose lithium batteries and batteries shipped separately from the device they power often have specific packaging and labelling requirements, while batteries installed inside a device are frequently treated differently again. If you sell anything battery-powered or containing batteries, this is one of the categories most worth checking specifically and regularly, since rules in this area are revised relatively often as safety standards evolve.

Liquids and perfumes

Liquids, including perfumes and aerosols, are often restricted rather than outright banned, generally requiring specific packaging (leak-proof, sometimes with volume limits) and, for air transport in particular, additional handling rules. Sellers of cosmetics, fragrances or liquid-based products should check current liquid-specific guidance carefully, since the rules can differ meaningfully between domestic and international shipments.

Counterfeit and restricted goods

Counterfeit goods, certain weapons or weapon parts, and various other regulated categories are prohibited for both legal and safety reasons — this is a firm category rather than a conditions-based one, and there's no packaging or declaration workaround. Sellers should also be aware that some legitimately manufactured items can resemble restricted categories closely enough to cause delays or seizure even when genuinely compliant, making accurate customs and content declarations — covered in our international shipping guide — particularly important for anything in an ambiguous category.

Perishables and living things

Perishable food, plants and live animals are generally restricted with specific conditions around packaging and permitted destinations, rather than universally prohibited — but the specifics vary enormously by item type and destination country, making this one of the categories where checking current, item-specific guidance matters most rather than relying on a general rule of thumb.

What happens if a prohibited item is discovered

Parcels found to contain prohibited items can be seized, destroyed or returned depending on the specific violation, and in some cases can carry legal consequences beyond simply losing the parcel — this isn't a purely commercial risk. For genuinely restricted (rather than prohibited) items, the more common outcome of non-compliant packaging or declaration is a delay while the parcel is queried or returned for correction, similar to the customs delays covered in our EU customs charge guide.

A sensible approach for sellers

If your product range includes anything in these categories — batteries, liquids, cosmetics, anything flammable or pressurised — build a habit of checking Royal Mail's current restricted items guidance whenever you add a new product line, rather than assuming last year's rules still apply or that a similar product being fine means every variation is too. It costs a few minutes and avoids a seized parcel, a frustrated customer, or worse.

Electronics, magnets and devices containing batteries

Beyond loose batteries, electronic devices with batteries built in — phones, laptops, some toys and tools — are frequently subject to their own specific rules, and items containing strong magnets can also trigger restrictions due to potential interference with aircraft navigation equipment on air-transported mail. If your product range includes consumer electronics of any kind, it's worth checking device-specific guidance rather than assuming general battery rules cover every case.

Cross-border differences for international shipments

Restrictions can differ meaningfully between domestic UK shipping and international shipments, since destination countries impose their own import restrictions on top of Royal Mail's outbound rules — an item that ships freely within the UK isn't automatically fine to send abroad. This is covered in more detail from the customs-declaration side in our international Click & Drop guide, but it's worth treating international restrictions as a genuinely separate check rather than an extension of domestic rules.

How this affects returns

Restricted items don't become unrestricted on the way back — a returned item containing a battery or liquid is subject to the same rules as the original outbound shipment, which is worth factoring into your returns process, covered in our Royal Mail returns guide, particularly if you sell anything in a commonly restricted category.

Building a simple compliance checklist

For sellers with a stable product range, a short written checklist — reviewed whenever a new product is added — covering whether it contains batteries, liquids, magnets, or anything pressurised or flammable, checked against Royal Mail's current guidance, turns this from a source of anxiety into a five-minute routine step rather than something re-researched from scratch each time a question comes up.

Why rules in this area change relatively often

Restricted item rules aren't static — they're periodically revised in response to safety incidents, aviation security requirements, and changes in international regulation, particularly around lithium batteries and other categories where the underlying risk has evolved as products themselves have changed. This is part of why a checklist needs revisiting periodically rather than being written once and treated as permanent — a product that was fine to ship two years ago under one set of rules isn't guaranteed to remain so indefinitely.

What to do if you're genuinely unsure about a specific product

For a product that doesn't clearly fall into an obvious safe or restricted category, the safest path is contacting Royal Mail directly for clarification before shipping at any volume, rather than relying on how a similar-seeming product was handled elsewhere or assuming a lack of an explicit ban means something is automatically fine. Getting this wrong at volume — rather than on a single parcel — multiplies the consequences considerably, since a systemic compliance issue affects every order shipped under the same assumption.

How this ties into supplier and sourcing decisions

If you're sourcing new products to sell, it's worth checking restricted item status as part of your sourcing decision itself, before committing to inventory — discovering after stocking a product that it's difficult or restricted to ship is a far more expensive mistake than checking upfront. This is particularly relevant for anything imported, where the product itself may already have required compliance documentation that's useful to have on hand if a shipment is ever queried.

Frequently asked questions

Can I ship perfume or aftershave with Royal Mail? Often yes, but typically with restrictions around packaging and volume due to the liquid and sometimes flammable alcohol content — check current guidance for the specific product rather than assuming all fragrances are treated identically.

Are lithium batteries always prohibited? No — they're generally restricted rather than prohibited, with different rules depending on whether they're loose, installed in a device, or shipped in bulk. Always check current battery-specific guidance before shipping.

What should I do if I'm not sure whether an item is restricted? Check Royal Mail's current official prohibited and restricted items list directly, and when genuinely uncertain, contact Royal Mail or a compliance advisor rather than guessing — the consequences of getting this wrong range from a returned parcel to a legal issue, so it's worth the extra few minutes.