The Windsor Framework introduces a new set of customs arrangements between Great Britain and Northern Ireland, designed to simplify shipping processes, reduce friction, and ensure smoother trade flow across the UK. It removes the need for unnecessary paperwork, checks, and duties on goods staying within the UK.

Taking effect from 1st May 2025, this framework replaces outdated processes with a more streamlined approach—dividing goods into two categories:

  • Not at risk: Staying in the UK

  • At risk: Potentially moving into the EU

Who is Affected?

This applies to all businesses shipping from Great Britain to Northern Ireland, whether B2B, B2C, or C2C.

❗ Important: While shipments remain within the UK, this is not considered domestic shipping. Commercial information must still be submitted electronically.

Green Lane vs Red Lane

The Windsor Framework introduces “green lanes” and “red lanes”:

  • Green lane: For goods not at risk (staying in NI); minimal checks; no commercial invoice required.

  • Red lane: For goods at risk (heading to EU); subject to full customs formalities.

Shiptheory ensures electronic shipment data is passed to carriers and customs, supporting both green and red lane compliance.

How to Prepare

Here are key steps Shiptheory users should take:

  1. Register for UKIMS (for B2B shipping)
    If you're shipping B2B and your goods are not at risk, you must register for a UK Internal Market Scheme (UKIMS) number.
    Apply via the UK Government site.

  2. Use Clear Item Descriptions
    Avoid vague terms like "samples". Use clear, plain-English names like "Linen shirts".

  3. Research Your Commodity (HS) Codes
    These are mandatory for B2B goods at risk of entering the EU, and recommended for all shipments.
    Find your HS codes here.

What Shiptheory Handles

While customs documents are no longer required, Shiptheory ensures the necessary commercial data is transmitted digitally, so you don’t need to generate physical paperwork. Here's what Shiptheory passes to carriers (based on your order and label data):

  • Sender name and address

  • Recipient name and address

  • Total order value

  • Parcel weight

  • Item quantity

  • Clear item descriptions

  • Commodity codes (where required)

  • UKIMS and EORI numbers (for B2B where applicable)


If your team is already using Shiptheory to automate shipping, most of the heavy lifting is already handled. Just ensure your product descriptions and HS codes are accurate, and register for UKIMS if you’re a B2B shipper.

We’ll continue to update our carrier integrations and documentation as each provider finalises their Windsor Framework compliance process.