What is S&S GB? UK Safety and Security Declarations Explained
- John Hall
- Customs Specialist at iCustoms.ai
S&S GB stands for Safety and Security Great Britain. It is the UK service, run by HMRC, that collects pre-arrival safety and security information on goods entering Great Britain and issues a reference number once a declaration is accepted.
In plain terms, S&S GB is the system you send a safety and security declaration through so Border Force can screen a shipment for risk before it arrives.
This guide explains what S&S GB is, how the S&S GB system works, how it relates to the ENS, who has to use it, and how to get set up. For deadlines, penalties and the full field list, we link to the dedicated guides rather than repeat them, so you can go straight to what you need. If you want the freight forwarder view, start with our S&S GB ENS guide.
What is S&S GB? (Safety and Security Great Britain)
S&S GB is the UK’s Safety and Security service for imports into Great Britain. You will also see it written as “Safety & Security GB” or “Safety & Security Great Britain (S&S GB)”. It is not a tax or duty system. Its single purpose is security: to gather advance data about a shipment so customs and Border Force can assess whether the goods pose a risk before they cross the border.
Three things define S&S GB:
- It is pre-arrival. The information is submitted before the goods reach Great Britain, and for deep-sea containerised cargo before loading.
- It is security, not revenue. It runs separately from the customs declaration that handles duty and VAT.
- It issues a Movement Reference Number (MRN). When a declaration passes validation, the S&S GB system returns an MRN as proof it was accepted.
S&S GB vs ENS: are they the same thing?
No, but they are two halves of the same process. The ENS (Entry Summary Declaration) is the declaration itself, the set of data about the shipment. S&S GB is the UK system you submit that ENS through. So when people search for “S&S GB ENS”, they are describing a UK Entry Summary Declaration filed via the S&S GB service.
The EU runs the same idea through a different system called ICS2. For a full breakdown of the declaration itself and how to complete it, see our complete ENS filing guide.
Why does S&S GB exist? The post-Brexit background
Before Brexit, Great Britain sat inside the EU’s common safety and security zone, so no separate declaration was needed for EU trade. After leaving the EU, the UK built its own safety and security regime, and S&S GB is the result. You can read the history in our piece on post-Brexit safety and security compliance.
Two dates matter. From 31 October 2024, a reduced dataset for ENS declarations came into force under the Border Target Operating Model (BTOM), cutting the number of fields required. From 31 January 2025, the waiver for EU imports ended, so safety and security declarations became required for goods moving from the EU into Great Britain, bringing EU trade in line with the rest of the world.
How the HMRC S&S GB system works
This is where S&S GB is more than a form. It is a live service that validates declarations and communicates outcomes back to you. In outline:
- Get a GB EORI. The party submitting the declaration needs a valid GB Economic Operator Registration and Identification (EORI) number.
- Complete S&S GB enrolment. Anyone filing through third-party software must enrol with S&S GB before they can submit. Holding an EORI on its own is not enough.
- Submit the ENS. The declaration is sent to the system, which validates it against the safety and security rules.
- Receive the outcome. A successful declaration returns an MRN; a failed one returns a rejection with the reason, so it can be corrected and resubmitted.
Behind the scenes, the S&S GB service exposes three sets of APIs that software connects to: one to create and amend declarations, one for notifications, and one for outcomes. Notifications include advanced interventions, where customs flag that they need to act on a consignment before it arrives, so you can respond in time. This two-way flow, submit, get validated, receive the outcome or an intervention, is what separates a live customs system from a static form.
Software that connects to these APIs can create declarations, receive notifications and pick up outcomes automatically, which is what makes high-volume filing workable. Our S&S GB ENS guide sets out the message flow in more detail.
Who must use S&S GB?
The legal responsibility sits with the carrier, the operator of the active means of transport bringing the goods in. In practice, freight forwarders and customs agents often file through S&S GB on the carrier’s behalf because they hold the shipment data, and importers may supply it. Whoever submits must hold a GB EORI and be enrolled.
One important limit: S&S GB cannot be used where the office of first entry is a Northern Ireland port. Northern Ireland follows separate arrangements. For more on who carries the duty when several parties are involved, see our guide on who is responsible for filing the ENS.
What information does S&S GB need?
Under the BTOM reduced dataset, a Great Britain ENS is built from 20 mandatory fields, up to 8 conditional fields, and 9 optional fields, covering the parties, the goods, and the transport and routing detail. We keep the full field-by-field reference in our complete ENS filing guide so this page stays focused on the system itself.
S&S GB deadlines, exemptions and penalties
The timing, the goods that are exempt, and the consequences of getting it wrong each deserve their own detail, so we cover them fully elsewhere. In short: declarations must be lodged before arrival, with the exact deadline set by transport mode; some movements such as certain personal effects are exempt; and late, missing or inaccurate declarations can lead to goods being held and to penalties. See our full S&S GB requirements and deadlines guide for the specifics.
S&S GB and the EU: how ICS2 compares
S&S GB handles goods entering Great Britain. The EU handles the same safety and security step through ICS2. The concept is shared, but the systems, data rules and deadlines differ, so a business trading both ways can need both. If your goods move into the EU as well, read our ICS2 guide alongside this one.
Getting set up on S&S GB with iCustoms
Enrolment, a valid EORI and a reliable route into the S&S GB APIs are the practical hurdles. iENS from iCustoms handles the filing end: it reads your shipping documents, extracts the data, validates the declaration before submission, and files through S&S GB to return the MRN, with the same platform covering EU ICS2. See how it works on the iENS Entry Summary Declaration page.
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