First Class is Royal Mail's fastest standard UK letter service, aiming for next-day delivery including Saturdays, with no tracking included.

What is Second Class?

Second Class is Royal Mail's cheapest standard UK letter service, aiming for delivery within 2-3 working days, with no tracking.

Signed For is an add-on to First or Second Class that requires a named signature on delivery and provides online tracking, but no compensation guarantee for delay.

What is Special Delivery Guaranteed?

Special Delivery Guaranteed is Royal Mail's premium next-day-by-1pm service, with full tracking, a named signature, and compensation cover up to £750.

Tracked 24 is Royal Mail's tracked parcel service aiming for next-day delivery, with online tracking but delivery to a safe place rather than a mandatory signature.

Tracked 48 is Royal Mail's slower, cheaper tracked parcel service, aiming for delivery within 2-3 working days with the same tracking as Tracked 24.

What is Recorded Delivery?

Recorded Delivery was Royal Mail's signature-on-delivery service until it was rebranded as Signed For in 2011 - the two names are often still used interchangeably.

What is Large Letter?

A Large Letter is a Royal Mail size category for items too big to count as a standard letter but not thick or heavy enough to be a parcel - roughly up to 353 x 250 x 25mm and 750g.

What is Local Collect?

Local Collect lets a recipient choose to pick up a tracked item from their local delivery office or a chosen Post Office branch instead of waiting for redelivery.

A safe place is a location a recipient nominates - like a porch or a specific neighbour - where a courier or postal worker can leave an item without a signature.

'Tracked' means an item's journey is scanned and visible online at each stage (collection, depot, out for delivery, delivered) - distinct from 'Signed For', which additionally requires a named signature.

What is Proof of Postage?

Proof of Postage is a free, stamped or receipted record from Royal Mail confirming an item was handed over for posting on a given date - it proves you sent something, not that it arrived.

What is Delivery Confirmation?

Delivery confirmation is the tracking event (and often an email or text) recorded once a tracked item is marked as delivered, with a timestamp and sometimes a photo or signature image.

What is Undeliverable as Addressed?

UAA mail is post that Royal Mail cannot deliver because the address is incomplete, incorrect, or the recipient is no longer there, and which is then returned to sender or sent to the National Return Letter Centre.

What is Return to Sender?

Return to Sender is the process of sending an undeliverable or refused item back to the address shown on the envelope, rather than destroying it.

Franking is printing a postage mark directly onto an envelope or label instead of using a stamp, usually via a franking machine or a bulk-mail printer.

A meter mark is the printed postage impression produced by a franking machine, showing the amount paid, the date, and the sender's franking licence details.

A postage stamp is a small, pre-printed adhesive or self-adhesive label that proves postage has been paid for an item sent by post.

What is Barcoded Stamp?

A barcoded stamp is a UK definitive stamp printed with a unique barcode next to the monarch's portrait, introduced from 2022 to support future 'Smart Stamp' technology and reduce fraud.

What is Definitive Stamp?

A definitive stamp is a standard, everyday postage stamp (such as the 1st and 2nd Class monarch-portrait stamps) sold on an ongoing basis, as opposed to a limited-run commemorative design.

Post Office & Royal Mail Glossary

Clear, accurate definitions for every common UK postal and Royal Mail term - delivery services, tracking, pricing, addressing and the organisations behind the post. 49 terms, in plain English, kept accurate and up to date.

Delivery services

First Class: First Class is Royal Mail's fastest standard UK letter service, aiming for next-day delivery including Saturdays, with no tracking included. First Class mail is not tracked and carries no guaranteed delivery date - Royal Mail's own target is 'aim to deliver the next working day, including Saturdays' rather than a contractual promise, so it is not suitable when you need proof a letter arrived. It costs more than Second Class in exchange for the faster aim. For anything time-sensitive but not legally critical, First Class strikes a reasonable balance; for anything with a deadline or dispute risk, Signed For or Special Delivery are safer.
Large Letter: A Large Letter is a Royal Mail size category for items too big to count as a standard letter but not thick or heavy enough to be a parcel - roughly up to 353 x 250 x 25mm and 750g. Royal Mail prices post by size band as well as weight: Letter, Large Letter, then parcel bands. A folded A4 document in a standard envelope is usually a Letter; the same document unfolded in a C4 envelope, or with a few extra pages, often becomes a Large Letter. Getting the size band wrong at a Post Office counter, or under-franking a Large Letter as a Letter, is one of the most common reasons Royal Mail surcharges the recipient for extra postage on delivery.
Local Collect: Local Collect lets a recipient choose to pick up a tracked item from their local delivery office or a chosen Post Office branch instead of waiting for redelivery. It is offered automatically as an option on many tracked Royal Mail services when a signature couldn't be obtained on the first delivery attempt, saving a second failed-delivery round trip.
Recorded Delivery: Recorded Delivery was Royal Mail's signature-on-delivery service until it was rebranded as Signed For in 2011 - the two names are often still used interchangeably. You may still see 'Recorded Delivery' used informally, in older correspondence, or by people repeating the older name - it now refers to what Royal Mail sells as Signed For.
Safe Place: A safe place is a location a recipient nominates - like a porch or a specific neighbour - where a courier or postal worker can leave an item without a signature. It applies mainly to non-signature tracked services; anything requiring Signed For or Special Delivery still needs a person to sign, so a safe place instruction does not apply to those.
Second Class: Second Class is Royal Mail's cheapest standard UK letter service, aiming for delivery within 2-3 working days, with no tracking. Second Class is the price-capped 'universal service' stamp - Ofcom regulates its maximum price because it is considered essential, whereas First Class pricing is set freely by Royal Mail. It suits routine correspondence with no hard deadline: invoices, statements, general letters. It is not tracked, so it should not be used for anything you may need to prove was sent or received.
Signed For (Royal Mail Signed For): Signed For is an add-on to First or Second Class that requires a named signature on delivery and provides online tracking, but no compensation guarantee for delay. It answers the question 'did it arrive, and who took it in?' - useful for contracts, notices, appeals and anything where you may need to prove receipt, not just posting. Signed For does not speed up delivery (it inherits the First or Second Class timescale) and offers limited compensation if the item is lost, so it is about proof rather than speed or high value.
Special Delivery Guaranteed: Special Delivery Guaranteed is Royal Mail's premium next-day-by-1pm service, with full tracking, a named signature, and compensation cover up to £750. It is the only Royal Mail letter service with a genuine contractual delivery guarantee (next working day by 1pm, including Saturdays for an extra fee), backed by compensation if that guarantee is missed. Use it for anything with a hard legal deadline - court documents, tribunal responses, tax deadlines falling the same or next day - where 'it should probably arrive in time' is not good enough.
Tracked 24: Tracked 24 is Royal Mail's tracked parcel service aiming for next-day delivery, with online tracking but delivery to a safe place rather than a mandatory signature. It sits between Signed For and Special Delivery: faster aim than Second Class Signed For, fully tracked, but - unlike Signed For - a signature is not always required, so it can be left in a safe place or with a neighbour. It is a parcel-weight service rather than a letter service, so it applies once an item exceeds large letter dimensions or weight.
Tracked 48: Tracked 48 is Royal Mail's slower, cheaper tracked parcel service, aiming for delivery within 2-3 working days with the same tracking as Tracked 24. Choose Tracked 48 over Tracked 24 when tracking matters more than speed - for example a paid item that is not urgent, but where both sender and recipient want visibility on progress.

Tracking & proof

Delivery Confirmation: Delivery confirmation is the tracking event (and often an email or text) recorded once a tracked item is marked as delivered, with a timestamp and sometimes a photo or signature image. For Signed For and Special Delivery items it includes the recipient's signature; for other tracked services it may just be a timestamp and GPS-based location, since no signature is captured.
Proof of Postage (PoP): Proof of Postage is a free, stamped or receipted record from Royal Mail confirming an item was handed over for posting on a given date - it proves you sent something, not that it arrived. It matters most for statutory deadlines: many UK legal and tax processes only require that a document was posted by a date, not received by it, so a certificate of posting can be the deciding piece of evidence in a dispute. Proof of postage is different from tracking - it is a one-off receipt at the point of sending, whereas tracking follows the item's whole journey.
Return to Sender: Return to Sender is the process of sending an undeliverable or refused item back to the address shown on the envelope, rather than destroying it. It only works if a legible return address is on the item - one of the reasons Royal Mail and most postal operators recommend always including one, even on First and Second Class mail with no tracking.
Tracked: 'Tracked' means an item's journey is scanned and visible online at each stage (collection, depot, out for delivery, delivered) - distinct from 'Signed For', which additionally requires a named signature. A tracked-but-not-signed item can still be marked delivered without anyone signing for it (for example, left in a safe place), whereas a Signed For item is only marked complete once someone signs.
Undeliverable as Addressed (UAA): UAA mail is post that Royal Mail cannot deliver because the address is incomplete, incorrect, or the recipient is no longer there, and which is then returned to sender or sent to the National Return Letter Centre. Common causes are an outdated address, a missing postcode or flat number, or a recipient who has moved without a redirection in place. UAA items that cannot be returned (no return address given) are eventually opened at the National Return Letter Centre to try to identify a sender.

Pricing & postage

Barcoded Stamp: A barcoded stamp is a UK definitive stamp printed with a unique barcode next to the monarch's portrait, introduced from 2022 to support future 'Smart Stamp' technology and reduce fraud. Royal Mail set a deadline after which older, non-barcoded stamps would no longer be valid for postage on their own, prompting many households to use up or exchange old stock. Always check the current Royal Mail guidance before posting with older stamps.
Commemorative Stamp: A commemorative stamp is a special, limited-run design issued to mark an anniversary, event, or cultural theme, remaining valid for postage like any other stamp. Examples include stamps marking royal events, popular culture anniversaries, and scientific milestones. They are popular with collectors (philatelists) as well as being usable postage.
Definitive Stamp: A definitive stamp is a standard, everyday postage stamp (such as the 1st and 2nd Class monarch-portrait stamps) sold on an ongoing basis, as opposed to a limited-run commemorative design. Definitives don't carry a printed price on UK stamps for 1st and 2nd Class - they are valid for that class of postage regardless of future price rises, which is why 'Non-Value Indicator' (NVI) stamps remain usable even after Royal Mail increases prices.
Franking: Franking is printing a postage mark directly onto an envelope or label instead of using a stamp, usually via a franking machine or a bulk-mail printer. Franked mail carries a machine-printed impression showing the postage paid, the date, and often the sender's account or licence number, which Royal Mail scans instead of a physical stamp. Businesses and services that print and post large volumes of letters use franking because it is faster than stamping by hand and usually cheaper per item than stamp price.
Meter Mark: A meter mark is the printed postage impression produced by a franking machine, showing the amount paid, the date, and the sender's franking licence details. It serves the same purpose as a stamp but is generated by a licensed franking machine rather than pre-printed and sold individually.
Non-Value Indicator (NVI): A Non-Value Indicator stamp shows a class of service ('1st' or '2nd') instead of a printed price, so it stays valid for that class even after Royal Mail raises prices. This is why a 1st Class stamp bought years ago at a lower price can still be used today - the stamp represents the service, not a fixed monetary amount.
Stamp (Postage Stamp): A postage stamp is a small, pre-printed adhesive or self-adhesive label that proves postage has been paid for an item sent by post. UK definitive (everyday) stamps now carry a barcode alongside the King's portrait; Royal Mail phased out non-barcoded stamps, giving a grace period during which they could be exchanged (or used with a Swap Out form) rather than accepted indefinitely.
Universal Service Obligation (USO): The Universal Service Obligation is Royal Mail's legal duty, set by Ofcom, to collect and deliver letters to every UK address six days a week at a uniform, affordable price. It is why a letter costs the same to send from London to a neighbouring house as to a remote Scottish island - the USO requires geographically uniform pricing, unlike most courier services which price by distance and location. Ofcom periodically reviews the USO, including proposals to reduce delivery days for some services, because letter volumes have fallen sharply while the cost of maintaining daily nationwide delivery has not.
Weight Band: A weight band is a price tier Royal Mail applies within each size category (Letter, Large Letter, parcel) - for example 0-100g, 101-250g - so cost depends on both size and weight. Getting size and weight bands right matters for anyone posting business mail at volume; under-paying postage results in a surcharge to the recipient rather than a returned item.

Addressing & mail handling

Care Of (c/o): 'Care of' (written c/o) on an envelope means the item should be delivered to a named person or organisation at that address on behalf of the actual addressee, who may not normally receive post there. It is used when sending to someone temporarily staying at, or associated with, an address that is not officially theirs - for example, mail for a guest sent 'John Smith, c/o Jane Doe, 12 Example Street'.
Delivery Office: A delivery office is the local Royal Mail depot responsible for the final sort and delivery of mail to addresses in a specific area, and where 'sorry we missed you' cards direct recipients to collect items. If a tracked item cannot be delivered (no one available to sign, for example), it is typically held at the local delivery office for a limited period before being returned to the sender.
Keepsafe: Keepsafe is a Royal Mail service that holds a customer's mail securely at the local delivery office while they are away, delivering it in one batch on their return. It is intended for temporary absences such as holidays, rather than a permanent change of address, which is what Redirection is for instead.
PO Box: A PO Box is a lockable mailbox rented from Royal Mail at a delivery office, giving a business or individual a postal address without disclosing a home or office street address. It is commonly used by businesses that want a professional postal address, people who want to keep a home address private, or organisations receiving high mail volumes that are better collected in bulk than delivered daily.
Postcode: A UK postcode is an alphanumeric code (like SW1A 1AA) that identifies a specific area down to a small group of addresses, used by Royal Mail to route and sort mail automatically. The outward code (e.g. SW1A) identifies the postal area and district; the inward code (e.g. 1AA) narrows it to a sector and often a single street, side of a street, or building. Automated sorting machines read the postcode to route mail with minimal manual handling.
Poste Restante: Poste restante is a service allowing mail to be sent to a named Post Office branch for collection by the addressee, useful for travellers or people without a fixed address. The recipient collects the item in person, usually with ID, rather than having it delivered to a home or business address. Availability varies by country and by individual branch.
Redirection Service: Royal Mail's Redirection service forwards mail addressed to an old address on to a new one for a set period (from one month up to two years), for a fee. It is commonly set up when moving house, to avoid missing post sent to an old address before every sender has been updated, and can be applied to an individual, a family, or a whole business.
Sorting Office: A sorting office (also called a mail centre) is a facility where post is sorted by destination, either by machine or by hand, before being sent on to local delivery offices. Large regional mail centres handle high-volume automated sorting using postcodes and barcodes; smaller local delivery offices then complete the final sort for individual postal rounds.

Business & bulk mail

Business Reply: Business Reply is Royal Mail's licensed reply-paid mail scheme, closely related to Freepost, allowing customers to reply without a stamp using a pre-printed reply envelope or card. It differs from a simple Freepost address mainly in the licensing and format requirements Royal Mail sets for the printed reply envelope or card design.
Freepost: Freepost is a Royal Mail service letting a business pay the postage on mail sent back to them by customers, so the customer posts a reply for free. It is commonly used for surveys, competition entries, returns, and application forms. The business registers a Freepost address or licence and is billed for every item that actually gets sent back, rather than paying upfront for unused capacity.
Hybrid Mail: Hybrid mail is a service where a document is created and submitted digitally, then printed, enveloped and posted by a third-party facility close to the delivery destination. It lets a business or individual 'print and post' a letter from a computer without owning a printer, envelopes, stamps or franking equipment - the model this glossary's own site is built on.
Mailmark: Mailmark is Royal Mail's 2D barcode system for bulk business mail, enabling automated sorting and item-level tracking data for large-volume senders. It replaced older barcode formats for bulk mailers and provides senders with delivery and performance data across a whole mailing, rather than tracking a single item the way a consumer tracked service does.
Response Rate (Direct Mail): Response rate is the percentage of recipients of a direct mail campaign who take the intended action (reply, order, visit a website), used to measure the mailing's effectiveness. Direct mail is often benchmarked against digital channels using this metric; despite lower volumes than email, physical mail response rates are frequently cited as higher per item because of lower inbox competition.

International

Customs Declaration (CN22/CN23): A customs declaration is a form (CN22 for lower-value items, CN23 for higher-value or restricted items) describing the contents and value of an item sent internationally, required by customs authorities. Documents-only letters with no commercial goods generally don't require a customs form, but anything containing goods, samples, or gifts sent abroad usually does. Incomplete or missing customs declarations are a common cause of delay or return for international parcels.
International Standard: International Standard is Royal Mail's basic overseas letter service, with no tracking and no compensation cover, similar in role to UK Second Class. It is the cheapest way to post a letter abroad but carries no proof of delivery, so it isn't suitable for anything time-sensitive, valuable, or requiring evidence of receipt.
International Tracked: International Tracked adds online tracking to an overseas letter or parcel, but delivery may not require a signature. It sits between the untracked International Standard service and the fully tracked-and-signed option, giving visibility of an item's journey abroad without mandating a signature on delivery.
International Tracked & Signed: International Tracked & Signed is Royal Mail's most secure overseas letter/parcel service, combining full tracking with a mandatory signature on delivery. It is the international equivalent of domestic Signed For, and the recommended choice for documents that must be provably received abroad - visa applications, legal paperwork, or time-critical filings sent to an overseas address.
Universal Postal Union (UPU): The Universal Postal Union is the United Nations agency that coordinates postal policy between countries, setting the rules that let mail move between national postal operators like Royal Mail and its overseas counterparts. Founded in 1874, the UPU is one of the oldest international organisations still operating, and its agreements are why a letter posted in the UK can be reliably delivered by a completely different national postal service overseas.

Organisations & history

Ofcom: Ofcom is the UK's independent communications regulator, which oversees Royal Mail's compliance with the Universal Service Obligation and caps the price of a Second Class stamp. Ofcom took over postal regulation from Postcomm in 2011. It periodically consults on the future of the USO, including proposals to change delivery frequency, in response to falling letter volumes.
Parcelforce Worldwide: Parcelforce Worldwide is Royal Mail's dedicated express parcel and courier subsidiary, handling larger and heavier items than the standard letters and parcels network. It operates alongside Royal Mail's core parcel services, generally used for bulkier, heavier, or more time-critical deliveries with courier-style tracking and named-day options.
Penny Black: The Penny Black, issued in 1840, was the world's first pre-paid adhesive postage stamp, introduced as part of Sir Rowland Hill's UK postal reforms. Before the Penny Black, postage was typically paid by the recipient based on distance travelled, which was expensive and often disputed. Hill's reform - a flat rate, pre-paid by the sender using a stamp - became the model postal services worldwide still follow.
Philately: Philately is the study and collecting of postage stamps and postal history, a hobby with dedicated clubs, exhibitions, and specialist dealers worldwide. The UK issued the first adhesive postage stamp in the world, the Penny Black, in 1840 - a landmark event in postal history that philatelists still treat as the hobby's founding moment.
Post Office Ltd: Post Office Ltd is a separate company from Royal Mail that runs the UK's network of Post Office branches, offering postal, banking, and government services over the counter. Royal Mail and Post Office Ltd were split into two distinct companies in 2012, ahead of Royal Mail's 2013 privatisation. Post Office Ltd remains government-owned and still sells Royal Mail stamps and services at its branches, alongside banking, bill payment, travel money, and ID/passport services.
Postie: 'Postie' is the common British informal term for a postal delivery worker, formally called a postperson or delivery operative. Royal Mail's official job title is 'Postal Delivery Worker' or similar, but 'postie' remains the everyday term used across the UK.
Royal Mail: Royal Mail is the UK's designated universal postal service provider, responsible for collecting and delivering letters and parcels to every UK address under the Universal Service Obligation. It traces its origins to a public postal service established under Henry VIII in 1516 and formalised by Charles I in 1635. It was a nationalised business for most of the 20th century, privatised in 2013, and is now owned by International Distributions Services (previously by EP Group after a 2024 takeover).

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