NCTS Phase 6 T1 Transit: What's Changing in 2025–2026 and What You Need to Do

Companies importing and exporting goods through the United Kingdom under T1 transit need to prepare for changes to the NCTS system. After the rollout of Phase 5 and its final state in January 2025, the UK is now moving to NCTS Phase 6 — in two stages. This article explains what already applies, what comes into force on 1 June 2026, and exactly what needs to change in how transit declarations are handled.

Where does NCTS Phase 6 come from?

NCTS (New Computerised Transit System) is the electronic system for handling customs transit under the Common Transit Convention (CTC). The EU has run NCTS for years, and each successive "phase" is a system upgrade — new messages, expanded data, integrations with other systems.

NCTS Phase 5 was rolled out in the UK in full from 1 July 2024. Phase 5's final state rules came into force on 21 January 2025 for all CTC countries simultaneously.

NCTS Phase 6 is the next generation — it includes changes to security types, the removal of certain security codes, and integration with the ICS2 Release 3 system. HMRC decided to roll it out in stages, because it was not able to implement the full Phase 6 by the deadline set by the European Commission (1 September 2025).

Stage 1: 1 September 2025 — what changed

On 1 September 2025, HMRC rolled out the first stage of NCTS Phase 6 (Phase 1). In practice, this was an update to the NCTS5 system with bug fixes, serving as a bridge to full Phase 6.

Important note for operators: A planned maintenance window took place on the NCTS GB and XI systems. Transit declarations lodged right before the maintenance window needed separate verification.

For day-to-day users there were few functional changes — the key procedural changes only come with stage 2.

NCTS Phase 5 final state — in force since 21 January 2025

Before we get to Phase 6, it's worth recapping what came into force under Phase 5's final state. These elements still apply and form the basis for the further changes:

Change	Status from 21.01.2025
Commodity codes	Mandatory for every goods item
Paper TAD (Transit Accompanying Document)	No longer mandatory — the electronic MRN is sufficient
Multiple house consignments	Available (not via the government portal)
Pre-lodged declarations	Available — can be submitted and amended in advance
Office of Incident	New feature for reporting incidents

Commodity codes are the one point that still trips up smaller companies. Since 21 January 2025, every goods item on a transit declaration must have a CN/HS code assigned — a missing code results in the declaration being rejected.

Stage 2: 1 June 2026 — the key changes for T1 declarations

Stage 2 of NCTS Phase 6 comes into force on 1 June 2026. This is the point that directly affects the day-to-day work of customs agents and transport operators. Below are the key changes announced by HMRC — before the rollout, confirm the exact scope and date in HMRC's transit newsletters.

Change to Security Types

Under the current NCTS5, four security types are available (0–3). After 1 June 2026, only the following will be available:

Type	Description	Available after 1.06.2026
0	No security	YES
1	ENS (Entry Summary Declaration)	NO — rejected
2	EXS (Exit Summary Declaration) — export from GB/NI outside the UK	YES
3	ENS + EXS (combined)	NO — rejected

Using type 1 or 3 after this date will cause the NCTS system to automatically reject the declaration and delay the movement of goods. If you use third-party software — check compatibility with your provider before 1 June 2026.

Removal of Incident Flags

From 1 June 2026, Incident Flags are no longer available on the NCTS screens linked to the IE007 message. In practice, this means incidents during transit (e.g. an accident or vehicle breakdown) must be reported directly at the nearest customs office, rather than recorded electronically after reaching the destination.

UK opt-out from TSAD/ICS2 integration

HMRC has decided that the United Kingdom will not implement the NCTS6 integration with ICS2 Release 3 (the EU's security control system). This means:

• Operators will keep lodging the transit declaration (NCTS) and the ENS declaration in ICS2 separately — there is no single combined declaration
• The three new NCTS6 messages linked to ICS2 (IE117, IE058, IE119) do not apply to UK movements
• The UK stays with its own GVMS (Goods Vehicle Movement Service) system for movements requiring a GMR

What you need to do — a checklist

If you handle T1 transit through the UK, check the following before 1 June 2026:

1. Customs software — has your provider published an update supporting only Security Types 0 and 2? If not — contact your provider urgently.
2. Declaration templates — review your saved declaration templates and remove Security Types 1 and 3.
3. Incident procedures — update your internal SOPs: road incidents during transit mean contacting the customs office, not raising an electronic flag.
4. Commodity codes — make sure every item has a CN/HS code (mandatory since 21.01.2025).
5. Team training — let your staff and subcontractors know about the changes to security types.

UK vs Europe — differences in the NCTS6 rollout timeline

It's worth knowing that the NCTS Phase 6 rollout timeline differs between CTC countries. For example, Norway rolled out NCTS Phase 6 in November 2025 as an "opt-out" country (without ICS2 integration). Poland and the other EU countries follow the European Commission's timeline — check the details of the rollout on the Polish side on the PUESC portal (puesc.gov.pl).

Frequently Asked Questions (FAQ)

Is a paper TAD still required? No. Since 21 January 2025, the paper TAD is no longer mandatory. The electronic MRN number is sufficient. Presentation of the goods takes place through GVMS or directly in the NCTS system.

What happens if I lodge a declaration with Security Type 1 after 1 June 2026? The NCTS system will automatically reject the declaration. The movement of goods will be blocked until a correct declaration is submitted. This results in delays and potential demurrage costs.

Does NCTS Phase 6 change the procedure for lodging T1 declarations at the PL/UK border? Yes, indirectly. The UK and the EU run on separate NCTS instances. T1 transit from the UK through Poland requires closing the UK transit (NCTS GB) and opening a new one in the EU's NCTS system. The changes to Security Types and the UK's opt-out from ICS2 do not affect the Polish side of the transit.

Where can I check the availability status of the NCTS GB system? On the HMRC website: NCTS availability and issues — GOV.UK.

How we help

agencjacelna.uk customs agency handles T1 transit declarations for imports from the UK to Poland and exports from Poland to the UK. We keep track of NCTS changes on an ongoing basis and update our systems in line with HMRC's timeline. If you have any doubts about the correctness of your T1 declarations after the Phase 6 changes — get in touch with us before shipping.

Sources

• New Computerised Transit System (NCTS) 6 — GOV.UK
• January 2025 — NCTS Phase 5: final state rules — GOV.UK
• CTC Traders API roadmap — HMRC Developer Hub

---

Need a T1 transit document under NCTS Phase 6?

We prepare T1/T2 transit declarations in line with the new NCTS Phase 6 system.

Call: +44 333 335 5072 or go to our contact form. An individual quote is provided once you've sent your documents.

A customs agency registered with CDS, UK EORI number.