# Peppol ID UK: how participant identifiers work
> A UK Peppol ID is a scheme code plus a value, such as 9932:gb123456789 for a VAT number. Here is the exact format, the case rules and which ID to use.
- Canonical URL: https://einvoices.uk/news/peppol-participant-id-uk
- Published: 20 October 2026 (2026-10-20)
- Last updated: 20 October 2026 (2026-10-20) (not updated since publication)
- Author: Floris Lindenaar, Editor, e-invoicing expert (https://einvoices.uk/authors/floris-lindenaar)
- Publisher: einvoices.uk (https://einvoices.uk)
- Type: Guide
- Topics: Peppol, Technical, 2029 mandate
- Language: en-GB (UK English); covers the United Kingdom
## Sources
- [Peppol Policy for use of Identifiers v4.4.0](https://docs.peppol.eu/edelivery/policies/Peppol-EDN-Policy-for-use-of-identifiers-4.4.0-2025-02-06.pdf)
- [OpenPeppol eDEC Code Lists](https://docs.peppol.eu/edelivery/codelists/)
- [Peppol BIS Billing](https://docs.peppol.eu/poacc/billing/3.0/bis/)
- [Peppol Service Metadata Publishing (SMP) v1.4.0](https://docs.peppol.eu/edelivery/smp/Peppol-EDN-Service-Metadata-Publishing-1.4.0-2025-02-06.pdf)
- [Peppol Directory - Search](https://directory.peppol.eu/public)
- [Tax update 2026: simplification, modernisation and fairness summary](https://www.gov.uk/government/publications/summary-of-tax-update-2026-simplification-modernisation-and-fairness/tax-update-2026-simplification-modernisation-and-fairness-summary)
## Key points
- A Peppol ID (participant identifier) is a four-digit scheme code and a value written as scheme:value, for example 9932:gb123456789 for a UK VAT number.
- Identifier values are treated case insensitive and may not contain spaces; the meta scheme iso6523-actorid-upis is always written in lower case.
- Most VAT-registered UK businesses on Peppol use scheme 9932 (UK VAT number); NHS trusts and many NHS suppliers use 0088 (GLN).
- The code list does not say whether 9932 values include the GB prefix, and 9932:gb123456789 and 9932:123456789 are different identifiers, so check how each customer is registered.
- The government has not yet said which identifier scheme UK businesses should use for the 2029 mandate.
---
A Peppol ID, properly called a **participant identifier**, is your address on the Peppol network. It always has two parts, a four-digit scheme code and the identifier value, written as `scheme:value`. A UK business using its VAT number would typically look like `9932:gb123456789` (all numbers in this article are made up).
## The anatomy of a Peppol ID
The rules are set by OpenPeppol's **Policy for use of Identifiers** (version 4.4.0, valid from 1 November 2025). Take this illustrative ID:
```
iso6523-actorid-upis::9932:gb123456789
```
| Part | Example | Meaning |
|---|---|---|
| Meta scheme | `iso6523-actorid-upis` | Peppol's fixed "Participant Identifier Meta Scheme" (POLICY 5). Always the same. |
| Separator | `::` | Joins the meta scheme to the identifier in SMP URLs and many tools |
| Scheme code | `9932` | Which register the number comes from. 9932 is "United Kingdom VAT number" |
| Separator | `:` | Joins the scheme code to the value |
| Value | `gb123456789` | The identifier itself |
Most of the time you will only see the short form, `9932:gb123456789`. The policy notes that the meta scheme "may be omitted in documents because it is currently constant". The long form with `::` is the format the SMP specification uses in lookup URLs, for example `https://smp.example.org/iso6523-actorid-upis::9932:gb123456789`.
## Where the ID appears
The same identifier turns up in several places, written slightly differently in each:
- **On the invoice (UBL):** in the seller's and buyer's `EndpointID`, with the scheme code as an attribute:
`GB123456789`
- **In the SMP:** `9932:gb123456789`
- **In the message envelope (SBDH):** `9932:gb123456789`
- **In the Peppol Directory:** shown as `9932:gb123456789`
Peppol BIS Billing 3.0 makes the electronic address mandatory for both sides. Rule PEPPOL-EN16931-R020 says "Seller electronic address MUST be provided" and PEPPOL-EN16931-R010 says the same for the buyer. If your customer's ID is missing from your customer record, the invoice will not validate.
## Case, characters and length
From the policy:
- **Case:** "All Participant Identifier values have to be treated case insensitive even if the underlying scheme requires a case sensitive value." So `9932:GB123456789` equals `9932:gb123456789`. The policy's own example: "0088:abc is equal to 0088:ABc", but "0088:abc is NOT equal to 0010:abc".
- **Meta scheme case:** `iso6523-actorid-upis` "is always case sensitive". Write it in lower case.
- **Characters:** values may use only letters, digits, `-`, `.`, `_` and `~`. **No spaces.** Write `gb123456789`, never `GB 123 4567 89`.
- **Length:** from 1 to 130 characters, not counting the scheme code.
For lookups, the policy requires the identifier to be lower-cased before it is hashed. That is why directories and lookup tools often show IDs in lower case.
## Which scheme should a UK business use?
The scheme code must come from the official Peppol participant identifier scheme code list (version 9.7, July 2026). The codes most relevant to UK businesses are:
| Code | Scheme | Typical UK use |
|---|---|---|
| 9932 | United Kingdom VAT number (GB:VAT) | Most VAT-registered UK businesses |
| 0088 | Global Location Number (GS1 GLN) | NHS trusts and many NHS suppliers |
| 0060 | D-U-N-S Number | Some large companies |
| 0199 | Legal Entity Identifier (LEI) | Financial and larger groups |
There is no code for Companies House numbers on the list, and no separate code for Northern Ireland or the Isle of Man. For more detail, see [Peppol EAS codes for the UK: 9932 and 0088](https://einvoices.uk/news/peppol-eas-codes-uk-9932-0088).
## GB prefix or no prefix?
The code list entry for 9932 gives no structure, example or validation rule. So it does not say whether the value should include the `GB` prefix. We searched the [Peppol Directory](https://einvoices.uk/news/peppol-directory-lookup-uk) on 20 October 2026. Most UK registrations under 9932 included it (`9932:gb` followed by nine digits), but a minority used nine digits on their own.
Those are two different identifiers. A sender looking up `9932:gb123456789` will not find a business registered as `9932:123456789`. Until the UK publishes rules, check how each customer is actually registered rather than assuming.
## Worked example
Acme Widgets Ltd (fictional) is VAT-registered as GB 123 4567 89 and connects through a certified provider.
1. Its provider registers the participant `iso6523-actorid-upis::9932:gb123456789` in its SMP and, usually, publishes a business card to the Peppol Directory.
2. Acme gives customers its Peppol ID: `9932:gb123456789`.
3. A customer's system puts `GB123456789` in the buyer party of any invoice sent to Acme.
4. The customer's provider looks up that ID, finds Acme's provider and delivers the invoice.
## What is not settled for the UK mandate
As of 20 October 2026, the government has confirmed Peppol as the core network. It has **not** published:
- which identifier scheme(s) UK businesses must or should register under
- whether 9932 values should include the `GB` prefix
- how VAT groups, divisions and branches should be identified
- whether the UK will request a new scheme code (for example for Companies House numbers)
The implementation roadmap is due at Budget 2026 on 28 October. We will update this guide when it is published.
## What to do now
1. Ask your provider which Peppol ID(s) it has registered for you, character for character.
2. Collect your customers' Peppol IDs and store the scheme code and value in separate fields.
3. Strip spaces from VAT-based IDs, and be consistent about the `GB` prefix.
4. If you supply the NHS, check whether you also need a GLN-based (0088) ID.
## Frequently asked questions
### What is a Peppol ID?
A Peppol ID (participant identifier) is the address other businesses use to send you documents over Peppol. It is a four-digit scheme code followed by a colon and the identifier itself, for example 9932:gb123456789.
### What is the Peppol ID for a UK company?
There is no single official UK format yet. In practice most UK VAT-registered businesses on Peppol use scheme 9932 (United Kingdom VAT number); NHS suppliers often use 0088 (GLN). The government has not yet said which scheme the 2029 mandate will expect.
### Is a Peppol ID case sensitive?
No. Peppol's Policy for use of Identifiers says participant identifier values must be treated case insensitive, so 9932:GB123456789 and 9932:gb123456789 are the same participant. The scheme part iso6523-actorid-upis is case sensitive.
### What does iso6523-actorid-upis mean?
It is the fixed name of Peppol's participant identifier meta scheme. It appears in SMP records, URLs and the message envelope, but you do not normally type it on an invoice.
### Can a business have more than one Peppol ID?
Yes. A business can be registered under several identifiers, for example a VAT-based ID and a GLN. Each ID is registered with exactly one SMP.
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How to cite: "Peppol ID UK: how participant identifiers work", einvoices.uk, 20 October 2026, https://einvoices.uk/news/peppol-participant-id-uk
einvoices.uk is an independent publication and is not affiliated with HMRC or the UK Government. Nothing here is tax advice; check the sources and official GOV.UK guidance before acting.