GB to NI Shipping After Brexit: The Paperwork Nobody Explains

Published 3 July 2026  ·  7 min read  ·  By Richard Brereton

Northern Ireland sits in a unique position after Brexit. It is part of the United Kingdom, but it remains aligned with EU single market rules for goods. The result is that moving goods from Great Britain to Northern Ireland — something that required zero paperwork before 2021 — now involves customs considerations that most small businesses and hauliers are still figuring out.

This guide explains the Windsor Framework requirements in plain English: what paperwork you need, when you need it, and how to find the right commodity code for your goods without spending hours on government websites.

The Core Problem: Two Lanes, One Border

The Windsor Framework, which replaced the Northern Ireland Protocol in 2023, created a two-lane system for goods moving GB to NI:

• Green Lane — for goods staying in Northern Ireland. Significantly reduced paperwork. Available to traders registered under the UK Internal Market Scheme (UKIMS).
• Red Lane — for goods at risk of moving onward into the Republic of Ireland (and therefore into the EU). Full customs declarations required.

The key question for any GB to NI shipment is: which lane do my goods fall into?

Green Lane: Who Qualifies?

To use the green lane, a trader must be registered under UKIMS. UKIMS registration is free and available to businesses established in the UK that move goods for final sale or use in Northern Ireland.

Green lane shipments still require some documentation, but the requirements are significantly lighter than full customs declarations:

• A simplified dataset submitted digitally (commodity code, description, value, origin)
• No import declarations for most goods
• No duty payable on goods remaining in NI

Red Lane: When Does It Apply?

Goods are considered "at risk" of entering the EU market if:

• The goods will be processed or sold in a way that could result in them moving to the Republic of Ireland
• The trader is not UKIMS registered
• The goods are on the list of commodities with specific EU market entry requirements (certain food products, animals, plants, chemicals)

Red lane movements require full customs entry — commodity codes, values, country of origin, duty calculation, and in some cases certificates and inspections.

Commodity Codes: The Biggest Friction Point

A commodity code (also called a tariff code) is a 10-digit number that classifies exactly what type of goods you are moving. Every shipment needs one. The wrong code can result in incorrect duty calculations, delays, and penalties.

The HMRC Trade Tariff is the official source, but navigating it for anything beyond the most common goods is genuinely difficult. The classification system has thousands of entries and significant ambiguity for composite or specialised products.

How to Find Your Commodity Code

There are two practical approaches:

1. HMRC Trade Tariff online tool — the official source at trade-tariff.service.gov.uk. Accurate but requires you to navigate a complex classification hierarchy.
2. NI Trade Guard Pro — a simplified lookup tool that pulls live HMRC data, gives you the commodity code, and shows the Windsor Framework paperwork requirements for that specific code. Built for hauliers and SME admins rather than customs specialists.

Common Goods and Their Requirements

General retail goods (clothing, electronics, furniture)

Typically green lane eligible for UKIMS-registered traders. Commodity code required. No duty if staying in NI.

Food and drink

More complex. Many categories require Sanitary and Phytosanitary (SPS) checks and health certificates, even in the green lane. The specific requirements depend on the commodity code and whether the product is of animal origin.

Plants and plant products

Require phytosanitary certificates. Some categories are prohibited entirely due to pest risk. Check the specific commodity code.

Medicines and medical devices

Northern Ireland remains aligned with EU rules for medicines. Specific batch testing and regulatory requirements apply.

What Hauliers Need to Know

If you are a haulier rather than a trader, your responsibility is to ensure you have the correct documentation from the trader before moving goods. The key documents to check:

• Commodity code for each line of goods
• UKIMS registration number (for green lane)
• Any required certificates (health, phytosanitary)
• Proof of destination (consignee details in NI)

Missing paperwork at the point of movement is significantly harder to resolve than getting it right beforehand.

Staying Current

Windsor Framework requirements continue to evolve. The phased implementation of the green lane system is ongoing, and the list of goods subject to specific requirements changes as new agreements come into effect. Checking the current status of your specific commodity code before each shipment — rather than relying on what was correct six months ago — is good practice.