The purpose of NCTS6 Phase 1 is to prepare the UK Transit system for the implementation of NCTS6 on the continent (for other contracted parties to the Union Common Transit Convention) while also releasing system bug fixes that should improve the NCTS experience in the UK.

NCTS6 Phase 1 release in the UK includes the following fixes for several known issues in NCTS5:

• Unloading Remarks Timestamp Issue: Currently, unloading remarks submitted between 00:00 and 01:00 BST are incorrectly treated as future dated.

This will be resolved, eliminating the need for the workaround of using the previous day’s date.

• National Transit Write-Off Issue: When the same trader handles both arrival and departure, the CC045 message is incorrectly linked to the arrival identifier.

This will be corrected.

• Reusable Local Reference Numbers (LRNs): NCTS currently rejects LRNs that have been cancelled and reused.

This restriction will be lifted.

• Unloading Remarks Rejections for Multiple House Consignments: When adding goods items sequentially within consignments, the system currently expects the sequence to follow the total number of goods items.

This will be fixed, and the current workaround will no longer be necessary.

• Successful message regeneration: Users will be able to ask the NCTS Helpdesk to resend a transit message that has already been successfully sent.

Important Note: Some third-party software providers may have implemented temporary workarounds for some or all of these issues. It is advisable to check with your third-party software provider to ensure that your systems will operate smoothly with these changes from September 1st.

The UK has also opted out of safety and security connectivity between NCTS6 and the ICS2 (Import Control System) for the time being. There is an option to opt in to this connectivity at a future date.

NCTS Planned downtime – 1^st September 2025

To support the deployment of NCTS6 Phase 1 (the NCTS5 update), there will be a short period of downtime affecting both the Great Britain (GB) and Northern Ireland (XI) NCTS services:

Both Great Britain (GB) and Northern Ireland (XI) services will be unavailable as follows:

1^st September: From 21:00 BST to 23.00 BST.

Both services are expected to be fully restored later that evening by 23:00 BST.

Messages related to submitted declarations during this time will be queued and issued once the services have been restored.

Important information during downtime

HMRC has reminded users to ensure that usual procedures for exports and imports are followed, such as obtaining a Goods Movement Reference when moving via a GVMS location.

Departures while NCTS is unavailable: 

It is recommended to avoid movements under the normal procedure that would require attendance at Inland Border Facilities (IBFs) or ports, and to avoid travelling to an IBF to commence a Transit movement until the system is restored to normal operability.

If it is essential that goods must be moved during downtime and it is not possible to submit declarations before the downtime begins, the manual fallback procedure is available as published in the Transit Manual Supplement.

A link to the Transit Manual Supplement can be found here: Transit Manual Supplement.

For arrivals into GB or XI. 

Movements should continue as per normal practice.

Some transit processes, such as the office of destination, may need to be completed when NCTS is next available.

Contact details for urgent support are given as follows:

• NCTS Helpdesk - ncts.helpdesk@hmrc.gov.uk or 0300 322 7095
• NCTS Supervising Office - isbc.nctssupervisingoffice@hmrc.gov.uk or 0300 322 9452.