What is a T1 transit document and when do you need one?

What a T1 is

T1 is the name the trade uses for a transit declaration for goods whose duty has not been settled yet. The goods move under customs supervision from an office of departure to an office of destination, and the duty and VAT are dealt with at destination. Between the UK, the EU and the other countries in the Common Transit Convention, transit declarations are made on the New Computerised Transit System (NCTS).

When you might need one

• Goods travelling from Great Britain across the EU to a country further on, so they are not cleared in every country they pass through.
• Goods your customer wants cleared at an inland customs office or at their own premises, rather than at the port.
• Goods arriving in Great Britain that you want to clear somewhere other than the port of arrival.

Whether a T1 is the right route depends on the goods, the route and where they will be cleared. That is the first thing we check.

What happens on the journey

• The declaration goes to the office of departure, which checks it before the goods are released.
• NCTS gives the movement a Master Reference Number (MRN).
• The goods travel with the Transit Accompanying Document (TAD). It can be shown digitally, as the MRN with its barcode, instead of on paper.
• At the end, the goods and the TAD are presented at the office of destination, which tells NCTS they have arrived.
• For a lorry crossing at Dover or Eurotunnel, the transit MRN also goes into the goods movement reference (GMR) before the crossing.

The guarantee

Every transit movement needs a guarantee covering the duty and VAT on the goods while they are in transit. It can be a single guarantee for one movement or a comprehensive guarantee that covers many. If a movement is not ended properly, the duty can be claimed under that guarantee.

Where it goes wrong

• The movement is never ended at destination, so it stays open and the holder of the transit and the guarantor are chased for it.
• The goods description is too vague. Since NCTS phase 5 went fully live on 21 January 2025, the first six digits of the commodity code are mandatory.
• The transit MRN is missing from the GMR, so the lorry cannot check in.

Checked against HMRC guidance on GOV.UK in November 2026: Using the New Computerised Transit System, NCTS phase 5 final state rules recap, Guarantors for transit. Rules change, so talk to us before you rely on this for a movement.