Tamper Evident Bags

Tamper evident bags, tamper proof security bags & evidence bags for cash, pharmacy, police & retail. Numbered void-seal bags in stock — free UK delivery.

• Tamper-evident security bags with tear-resistant material
• Sequential numbering for tracking and auditing
• Tear off receipt for chain of custody
• Available in opaque and clear styles

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Tamper Evident Bags — Secure, Numbered, Void-Seal Security Bags

Our tamper evident bags are designed to give you visible proof if anyone has interfered with the contents in transit. Every bag uses a permanent void-seal closure that reveals a hidden "OPENED" message the moment it's lifted, along with a unique sequential number and matching tear-off receipt for full chain-of-custody tracking. They're a fast, affordable alternative to lockable bags and paper security envelopes, and the format that retail, banking, pharmacy and security professionals across the UK rely on.

What is a tamper evident bag?

A tamper evident bag (sometimes called a tamper proof bag or tamper resistant bag) is a single-use polythene security bag with a permanent adhesive strip. Once sealed, the bag can't be opened without leaving clear visual evidence — the void pattern appears across the seal and the bag itself cannot be re-closed. Each bag carries a unique number printed on both the body and the tear-off receipt, so it can be logged at dispatch and re-checked on arrival.

While "tamper proof" suggests no one can ever open the bag, in reality no bag is truly impossible to breach. The industry standard — and what every reputable supplier actually ships — is tamper evident security bags that make any breach impossible to hide.

Tamper proof security bags for every use case

Our security bags are trusted across a wide range of industries:

• Cash-in-transit & banking — secure cash deposits, till lifts and end-of-day takings between branches, ATMs and the bank.
• Retail loss prevention — high-value returns, in-store transfers and shrinkage investigations.
• Pharmacy & medical — controlled drug transfers, prescription deliveries and patient property bags.
• Legal & confidential documents — solicitor file transfers, signed contracts and confidential mail.
• Courier & high-value dispatch — jewellery, electronics, precious metals and any single-trip shipment where the recipient needs to know the parcel arrived intact.

Evidence bags & police evidence bags

Our security bags double as evidence bags for police forces, private investigators, forensic teams and corporate security departments. The sequential numbering, tear-off receipt and write-on panel are exactly what's required for proper chain-of-custody evidence handling. Clear film options allow the contents to be inspected without breaking the seal, while opaque bags hide sensitive items from view in transit. Whether you need a small batch of police evidence bags for a single investigation or a regular wholesale supply, you'll find the size and format in our range above.

Security envelopes & lockable bag alternatives

If you're currently using paper security envelopes or reusable lockable bags, it's worth knowing where tamper evident bags fit:

• vs security envelopes — tamper evident bags are water resistant, tear resistant and far harder to breach undetected than a paper envelope.
• vs lockable bags — lockable bags suit recurring transport routes where the same bag is reused. Tamper evident bags are cheaper per use, lighter to carry and ideal for single-trip secure dispatch.

How our void-seal security bags work

• Permanent void-seal closure — peel the release strip, fold and press. The seal cannot be reopened without revealing the void message.
• Sequential numbering — every bag carries a unique reference number, printed on the bag and on a matching tear-off receipt.
• Tear-off receipt — keep the perforated stub as your dispatch record; the recipient checks the number against the bag on arrival.
• Opaque polythene film — durable, water resistant and tear resistant, so the contents stay protected as well as secure.
• Write-on panel — record the date, contents, sender and recipient directly on the bag.

Choosing the right size

Pick the bag size from the pricing table above based on the largest item you'll typically send — there should be a small amount of slack for the seal to fold flat once the bag is full. As a guide: smaller sizes suit cash bags, prescriptions and documents up to A5; medium sizes cover A4 paperwork, file bundles and small valuables; larger sizes handle bulkier returns, multi-item evidence and parcels up to A3+.

UK stock & fast dispatch

All sizes are held in stock at our UK warehouse and dispatched the same working day on orders placed before 2pm. Delivery is free on orders over £150, or a flat £4.99 otherwise. For pallet quantities, custom numbering or printed branding, use the bulk enquiry form below.

Tamper proof packaging & tamper evident packaging explained

Tamper proof packaging and tamper evident packaging are used interchangeably, but they describe different things. Tamper proof implies a pack that cannot be opened at all, which no flexible bag can honestly claim. Tamper evident packaging — what we supply — is designed so that any breach is permanently and obviously recorded on the pack itself. For dispatch, cash handling and secure transfer, that visible proof is what auditors, insurers and recipients actually need.

Tamper evident cash bags

Used as tamper evident cash bags, these security bags cover till lifts, end-of-day takings, ATM replenishment, cash-in-transit collections and branch-to-branch transfers. The sequential number is logged against the deposit, the tear-off receipt stays with the sender, and the cash office checks the number and seal on arrival. For loose change and denomination sorting, our plain coin bags for banking are the cheaper option.

Buy tamper evident bags in the UK

Every size is held in stock in our UK warehouse and dispatched the same working day on orders placed before 2pm, so you can buy tamper evident bags UK-wide with next-day delivery. Trade and wholesale pricing applies automatically as quantities increase in the table above, and bespoke sizes, custom number ranges and printed branding are available on request.

Looking for evidence bags?

If your use case is evidence handling rather than dispatch, our dedicated evidence bags page covers police, forensic and investigative formats in clear and opaque film. You can also compare the full security bags range, including cash bags and security envelopes.