HMRC has released the following information about Phase 6 of the New Computerised Transit System via the Joint Customs Consultative Committee.

As outlined in our previous communications, the New Computerised Transit System, Phase 6 (NCTS6) is scheduled for deployment on Monday, 1 June 2026.

Planned system downtime reminder - 1 June 2026

To support the deployment of NCTS6, there will be a brief period of downtime for both the Great Britain (GB) and Northern Ireland (XI) NCTS services:

• Both Great Britain (GB) and Northern Ireland (XI) services will be unavailable from 07:00 (BST) on 1 June 2026 and are expected to be fully restored by 09:00 (BST) on 1 June 2026
• Messages relating to Inbound and Outbound movements generated during the scheduled downtime will be ‘queued’ until the service has been restored and should then progress as normal.
   

Important information about the status of submitted declarations

Departures:

• We recommend that all departure declarations submitted before 07:00 BST on 1 June 2026 reach at least ‘Accepted’ status to minimise the risk of disruption to the movement
• However, based on testing, we are confident that movements still in ‘Submitted’ status when the service becomes unavailable are unlikely to be adversely affected. This is due to the minimal differences between NCTS5 and NCTS6. Therefore, any declarations submitted in NCTS5 and progressing in NCTS6, should continue without issue
• Any declarations that are ‘rejected’ will need to be resubmitted once the system becomes available
• Whilst NCTS is unavailable, we strongly recommend you avoid starting any Departure movements under the normal procedure, which require attendance at Inland Border Facilities (IBFs) or ports

If you must move goods during the downtime, please ensure the relevant declarations are submitted before the downtime begins. If you cannot do this, you may use the Business Continuity Procedure, however we strongly advise against travelling to an IBF or port to start a transit movement until the system is back online. You can find the business continuity processes in the Transit Manual Supplement.

Arrivals:

For arrivals into GB or XI, you should continue your movements as usual. Some transit processes, such as Office of Destination, may need to be completed once NCTS is available again.

Escalations during downtime

If you require urgent support during this time, please contact:

• NCTS Helpdesk – ncts.helpdesk@hmrc.gov.uk - Service level: responses within 5 working days.
• NCTS Supervising Office – isbc.nctssupervisingoffice@hmrc.gov.uk - Service level: responses within 4 hours.

HMRC will issue communications and update our service availability page to confirm when each service has successfully gone live.

Important – for users of third-party software

If you use third-party software, please note that your software provider will need to set up their service to send and receive messages with a new API as part of their migration from NCTS5 to NCTS6 – this can only be done during the planned downtime noted above.

Your software provider will confirm when you can start using their updated service on 1 June. Please do not use your NCTS service until your provider has confirmed that it is ready to use.