The Windsor Framework became fully operational on 1 May 2025, and the rules now apply to every UK eCommerce business shipping to Northern Ireland. If you sell on Shopify, Amazon, eBay, WooCommerce or your own site, and you fulfil orders to NI customers, you are affected.
The post-Brexit picture has been confusing. The Northern Ireland Protocol, the Windsor Framework, UKIMS, NIRMS and now further VAT updates in 2026 have stacked on top of each other, with each layer adding new acronyms and obligations. This guide pulls it all together for online retailers, 3PLs and the operations teams behind them.
We will cover what the Windsor Framework changed, what UKIMS is, how the green and red lane system works in practice, what it means for fulfilment operations, and why smarter trade rules also support more sustainable eCommerce.
What is the Windsor Framework
The Windsor Framework is a 2023 agreement between the United Kingdom and Europe that replaced parts of the original Northern Ireland Protocol. It reshaped how goods move between Great Britain (England, Scotland and Wales) and Northern Ireland, making cross-Irish-Sea trade significantly easier for most businesses.
According to the UK Government’s Windsor Framework publication, the Framework was agreed on 27 February 2023 and formally adopted at the Withdrawal Agreement Joint Committee on 24 March 2023. The full set of arrangements, including the customs green lane, came into operation on 1 May 2025.
Key dates:
- 27 February 2023 — Agreement announced
- 24 March 2023 — Formally adopted
- 1 October 2023 — First arrangements for retail food and drink began under NIRMS
- 1 May 2025 — Full Windsor Framework arrangements in effect
The Framework has three stated goals: restoring the smooth flow of trade within the UK internal market, safeguarding Northern Ireland’s place in the Union, and addressing the democratic deficit that sat at the heart of the original Protocol.
How the Windsor Framework Differs from the Northern Ireland Protocol
Under the original Protocol, GB-to-NI movements were treated almost like exports to the EU. Customs declarations, regulatory checks and additional paperwork applied to a wide range of goods, even when they were destined to stay in Northern Ireland.
The Windsor Framework changes that. Eligible goods staying in NI now move under the UK internal market, with simplified processes, reduced paperwork and no EU customs duty. Full EU rules apply only where goods are genuinely at risk of entering the EU single market.
For UK eCommerce brands, the practical result is fewer delays, lower admin costs and a clearer path to fulfilling Northern Ireland customer orders without treating them like international exports.
What is UKIMS
UKIMS stands for the UK Internal Market Scheme. It is the HMRC authorisation that allows a business to declare goods as “not at risk” of entering the EU when moving them from Great Britain to Northern Ireland. With UKIMS authorisation, eligible goods avoid EU customs duty and qualify for the simplified processes introduced under the Windsor Framework.
A UKIMS number is the unique authorisation reference HMRC issues once registration is approved. It is used on customs declarations to prove eligibility for the simplified GB-to-NI route.
UKIMS replaces the earlier UK Trader Scheme. Existing UKTS authorisations were transferred over, and any new business moving goods to NI for sale or end-use needs to apply through HMRC’s UKIMS authorisation process directly.
UKIMS vs EORI
Two different numbers, two different purposes:
| Number | What it does |
| EORI | Identifies a business for any customs activity in the UK or EU |
| UKIMS | Authorises that business to use the simplified GB-to-NI process under the Windsor Framework |
You need both. The EORI gets you into the customs system. UKIMS unlocks the green lane within it.
Who Needs to Register for UKIMS
UKIMS authorisation is for businesses, not individuals. The scheme applies to:
- eCommerce sellers shipping to Northern Ireland customers
- 3PLs handling NI fulfilment on behalf of brands
- B2B suppliers selling into NI retail or trade
- Businesses moving regulated goods such as agrifood, plants or chemicals into NI
If you are a private individual sending the occasional parcel to a friend or family member, UKIMS does not apply to you.
What a UKIMS Number Looks Like on Customs Declarations
For businesses or 3PLs that submit their own customs declarations rather than going through the Trader Support Service, three specific codes need to be entered correctly:
- Document Code (DE 2/3) – “1UKI” followed by the UKIMS authorisation number
- Importer Identification Number (DE 3/16) – the EORI number linked to the UKIMS registration
- Authorisation Type Code (DE 3/39) – “UKIM” followed by the EORI number
Getting these wrong can result in goods being treated as “at risk” and incurring EU customs duty unnecessarily. Most online retailers will not handle these declarations themselves, but it is worth knowing what your courier or 3PL is submitting on your behalf.
The Green Lane and Red Lane System
The green and red lane system is the central change every eCommerce brand needs to understand. It determines whether your goods move quickly with minimal paperwork or face full EU customs checks.
The Green Lane
The green lane is for goods that stay in Northern Ireland under UKIMS authorisation. It uses what HMRC calls Simplified Processes for Internal Market Movements (SPIMM).
As outlined by the Northern Ireland Customs and Trade Academy, eligible goods under SPIMM move with:
- A simplified dataset called Internal Market Movement Information (IMMI) rather than a full customs declaration
- A Trader Goods Profile (TGP) that lets businesses pre-load common product information so they don’t need to provide a commodity code on every movement
- No EU customs duty
- Faster transit and reduced paperwork
To use the green lane, one of the parties moving the goods must hold UKIMS authorisation, and the goods must meet the criteria for being “not at risk” of entering the EU.
The Red Lane
The red lane is for goods that are at risk of entering the EU market, typically because they are passing through NI to the Republic of Ireland or other EU countries, or because they don’t meet the eligibility criteria for SPIMM.
Red lane goods are subject to:
- Full customs declarations
- EU regulatory compliance checks
- The applicable EU rate of duty
The goal of the system is to maintain frictionless trade within the UK while protecting the integrity of the EU single market.
Related Schemes Every eCommerce Brand Should Know
The Windsor Framework is not just about the green and red lane. Several supporting schemes affect specific product types and movement methods, and most online retailers will encounter at least one.
NIRMS (Northern Ireland Retail Movement Scheme)
NIRMS started on 1 October 2023 and is designed for prepacked retail goods including food, drink, pet food and food contact materials. Registered businesses can move eligible consignments using a single General Certificate supported by a packing list, without needing veterinary or plant health inspector approval.
If you sell food, drink, pet products or supplements through eCommerce channels and ship to NI consumers, NIRMS is the scheme that affects you most directly. Full registration guidance is available on the NIRMS page on GOV.UK.
NIPHL (Northern Ireland Plant Health Label) Scheme
NIPHL allows growers and traders to move plants, seeds and used agricultural machinery from GB to NI without phytosanitary certificates, as long as the goods stay in NI. Less relevant for most eCommerce brands, but important if your range includes live plants, seeds or gardening products.
UK Carrier Scheme for Consumer Parcels
This is the scheme most online retailers will engage with in practice. The UK Carrier Scheme is an authorisation held by parcel carriers that allows them to move eligible consumer parcels from GB to NI without completing customs or safety and security declarations.
Carriers like Royal Mail, Yodel, Evri, DPD and other express operators are working under these arrangements for B2C consumer movements. The information required for parcel movements is collected by the carrier directly and submitted to HMRC through their own systems, not through the Trader Support Service portal.
For a Shopify, Amazon or eBay seller fulfilling NI orders, this means the courier handles most of the customs side at the parcel level, provided the carrier is operating under the scheme. Business-to-business movements still follow the freight rules and can use SPIMM if eligible.
Duty Reimbursement Scheme
If a business has paid EU duty on “at risk” goods that ultimately stayed in NI, were moved to GB, or were exported outside the EU, the Duty Reimbursement Scheme allows them to reclaim it. Claims are backdated to 1 January 2021. This is particularly relevant for brands that overpaid duty in the early post-Brexit period before the Windsor Framework arrangements came into full effect.
What This Means for UK eCommerce Brands
Beyond the policy detail, the practical question for online retailers is straightforward. How does this change the way you ship to Northern Ireland customers?
Shipping to Northern Ireland Customers
For a Shopify, Amazon or WooCommerce seller fulfilling NI orders direct from a GB warehouse, the Windsor Framework should mean fewer delays, no EU duty on eligible goods and a cleaner customer experience at the point of delivery. The catch is that you, your 3PL or your carrier needs the right authorisations in place.
Without UKIMS authorisation somewhere in the chain, NI orders may be treated as “at risk” and hit with EU duty, plus the additional paperwork and delay that goes with it.
How a 3PL Handles This for You
A UKIMS-authorised 3PL can move client stock to NI customers under SPIMM without each individual brand needing to manage the paperwork themselves. A competent fulfilment partner will:
- Hold UKIMS authorisation on behalf of clients moving eligible goods
- Maintain Trader Goods Profile data for the products they fulfil
- Submit IMMI through the Customs Declaration Service or via TSS where appropriate
- Coordinate with carriers operating under the UK Carrier Scheme for B2C consumer parcels
- Provide reporting and visibility on NI movements alongside the rest of your fulfilment data
For brands selling internationally, the value of having NI handled inside your existing fulfilment relationship is clear. It avoids the need to set up separate shipping rules, courier accounts or customs processes specifically for Northern Ireland.
2026 VAT and Excise Updates
The Windsor Framework gives the UK Government greater flexibility on VAT and excise rates for goods sold in Northern Ireland, while keeping EU rules in place where goods could enter the single market. VAT and excise arrangements for NI continue to evolve, and 2026 includes further updates on specific product categories.
Always check the most recent HMRC guidance for your product type before publication or pricing decisions, particularly for categories like alcohol and energy products where excise rules are more complex.
Windsor Framework and Sustainability
This connection rarely gets discussed, but it matters for any eCommerce brand running a lower-impact supply chain.
Smoother customs means fewer rejected and re-routed shipments. Fewer reroutes means lower freight emissions per parcel, less wasted packaging on damaged or returned goods, and better load utilisation for the carriers moving stock across the Irish Sea. Predictable lanes also let 3PLs consolidate consignments more efficiently rather than splitting loads to manage red-lane risk.
Cain Fleming, co-founder of Green Fulfilment, puts it plainly:
“Customs friction is environmental friction. Every time a shipment gets rejected, re-routed or sent back, that’s extra mileage, extra packaging and extra emissions baked into the same order. Getting Windsor Framework eligibility right is part of running a leaner supply chain, and a leaner supply chain is almost always a greener one.”
For purpose-led brands, choosing a 3PL that handles UKIMS, NIRMS and carrier coordination efficiently is part of the wider sustainability picture, alongside packaging choices, paperless dispatch and energy-efficient warehousing.
How to Register for UKIMS
The application process runs through HMRC. There is no strict deadline for registration, but the longer a business operates without UKIMS, the more likely it is to incur unnecessary EU duty on NI movements.
Step 1. Check Eligibility
Your business must be UK-based and meet HMRC’s requirements around record-keeping, compliance and systems. The goods you move must qualify as “not at risk” of entering the EU, meaning they are destined for sale or final use in Northern Ireland.
Step 2. Apply Online via HMRC
Submit the application through GOV.UK. You will need to provide business details, your EORI number and evidence that you can track goods through your supply chain reliably enough to demonstrate the “not at risk” status.
Step 3. Receive Your UKIMS Authorisation
Once approved, HMRC issues your UKIMS authorisation number. This is the reference that goes onto customs declarations, either directly through CDS or via the Trader Support Service.
Step 4. Apply for Related Schemes If Needed
Depending on your product range, you may also need:
- NIRMS for prepacked retail food, drink and pet food
- NIPHL if you move plants, seeds or used agricultural machinery
- Confirmation that your carrier operates under the UK Carrier Scheme for B2C parcels
Common Mistakes to Avoid
Five things businesses get wrong with UKIMS and Windsor Framework movements:
- Treating UKIMS and EORI as the same thing. They are separate authorisations and you need both
- Assuming individual customers need UKIMS. They do not. The scheme is only for commercial movements
- Forgetting to update Trader Goods Profile when product range changes. Out-of-date TGP data can invalidate IMMI submissions
- Submitting full customs declarations when SPIMM applies. This adds cost and time for no reason
- Skipping authorisation entirely. Without UKIMS, eligible goods get hit with EU duty even when they are staying in NI
Frequently Asked Questions
What is the Windsor Framework in simple terms
The Windsor Framework is a 2023 UK-EU agreement that replaced parts of the Northern Ireland Protocol and made it easier for businesses to move goods between Great Britain and Northern Ireland. It introduced a green and red lane system, simplified customs processes, and reduced paperwork for goods staying in NI.
What does UKIMS stand for
UKIMS stands for UK Internal Market Scheme. It is an HMRC authorisation that lets businesses declare goods as “not at risk” of entering the EU when moving them from Great Britain to Northern Ireland.
What is a UKIMS number
A UKIMS number is the unique authorisation reference HMRC issues once your application is approved. It appears on customs declarations as part of the codes that prove your goods qualify for the simplified GB-to-NI process.
Do I need UKIMS to ship from Great Britain to Northern Ireland
Yes if you are a business moving goods commercially. Without UKIMS authorisation somewhere in your supply chain, your goods may be treated as “at risk” of entering the EU and charged EU customs duty. Individuals sending personal parcels do not need UKIMS.
How does the Windsor Framework affect Shopify or Amazon sellers shipping to Northern Ireland
For most B2C eCommerce sellers, the practical day-to-day effect is handled by your courier under the UK Carrier Scheme. For larger consignments, B2B movements or stock transfers to a 3PL in NI, you or your fulfilment partner will need UKIMS authorisation to use the green lane.
What is the difference between the green lane and red lane
The green lane is for goods staying in Northern Ireland under UKIMS authorisation, with simplified paperwork and no EU duty. The red lane is for goods at risk of entering the EU, which face full customs declarations and EU regulatory compliance checks.
When did the Windsor Framework come into effect
The Windsor Framework was agreed in February 2023 and adopted in March 2023. Phased implementation began in October 2023 with NIRMS for retail goods, and the full set of arrangements including the customs green lane came into operation on 1 May 2025.
Sources referenced in the article:
- gov.uk Windsor Framework publication (key dates and Framework adoption)
- HMRC UKIMS application guidance (registration process)
- Northern Ireland Customs and Trade Academy (SPIMM, IMMI, TGP definitions)
- gov.uk NIRMS guidance (retail movement scheme)
