The Trader Support Service (TSS) launched the Assisted Completion Service in June 2022 to help businesses complete their Supplementary Declarations (SD).

With the Assisted Completion Service, a TSS agent will complete up to five SDs a month on behalf of a business for goods movements from Great Britain to Northern Ireland. This includes organising, validating and entering data to the TSS Postal, submitting the SD, and helping resolve any errors.

The new service is available to all traders, and can be accessed directly on the TSS Portal or by calling the TSS Contact Centre on 0800 060 8888.

Further information regarding the Assisted Completion Service is available on the NI Customs and Trade Academy site:

Brief overview: TSS Assisted Completion Service – Northern Ireland Customs and Trade Academy (

Quick guide: Assisted Completion Service quick guide – Northern Ireland Customs and Trade Academy (

Detailed guide: Assisted Completion Guide – Northern Ireland Customs and Trade Academy (

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