Every international haulier eventually meets the T1: the customs transit declaration that lets goods cross multiple borders without being customs-cleared at each one. It is the plumbing behind a Calais-to-Warsaw run that does not stop for import formalities at every frontier - duty and import formalities are suspended en route and settled at destination. The system that runs it is the New Computerised Transit System, and HMRC’s guidance on NCTS is the authoritative map.
NCTS is the online system for submitting transit declarations and notifications to HMRC. If you are a UK trader, you must use NCTS to move goods under the Common Transit Convention - the procedure usable for movements between the UK, the EU and the other common transit countries. There are edges to know. The system cannot be used for certain goods moving by air, sea or rail, for certain movements between approved temporary storage facilities, or to submit proof of Union status T2L documents. And TIR movements - transit operations beginning, ending or passing through a third country signed to the TIR convention - must be declared to NCTS for any part of the journey within Northern Ireland or the EU.
The pre-movement checklist is specific: an EORI number or common transit country trader identification number; your business address; a guarantee; the Customs Declaration Service entry number for free circulation goods; details of the vehicle transporting the goods; and a description of the goods. The guarantee deserves emphasis, because it is the financial heart of transit: duty is suspended, not waived, and the guarantee is what stands behind the suspended amount until the movement is correctly closed out. Transit simplified procedures are available for regular users - the authorised consignor and consignee arrangements that let movements start and end at traders’ own premises rather than customs offices.
Goods moving under transit may be accompanied by a Transit Accompanying Document - the TAD - for presentation at destination. It earns its keep when things go wrong: if the goods are diverted, or there are incidents during transit, the TAD is the movement’s identity. The document carries the consignment’s Master Reference Number printed in numeric form and as a barcode, and the barcode specification is strict - printed to the ISO code 128 standard rather than EAN 128. When consigning multiple items, a list of items must be included with the TAD. Traders can print the TAD and list at their own premises with a printer configured for the legally required format; if the printer is not up to it, the TAD can be printed at the office of departure instead. The system authenticates the document, so customs do not need to stamp it.
The transit declaration belongs to the trader - but the haulier carries its consequences. The vehicle details on the declaration are the truck at your dock; the TAD, where used, rides in your cab; and the movement only closes out cleanly when the goods and their status arrive at the destination as declared. So carriers should treat the MRN as a first-class reference: confirmed before departure, matched against the goods movement reference where GVMS ports are used - remembering that transit MRNs and import declaration references have their own rules about what can appear together - and handed over intact at delivery. Transit is one of the great simplifications of European road freight: borders without stops, duty settled at destination. It works precisely because everyone in the chain, carrier included, keeps the references straight.
The suspension that makes transit efficient is also what makes errors expensive. Because duty is suspended on the strength of the declaration and the guarantee, a movement that fails to close out correctly - goods not presented at destination, the discharge never recorded - leaves the suspended duty hanging over the guarantor. Hauliers see the edge of this when a delivery goes wrong: a refused load, a diverted trailer, goods seized en route. In every one of those events the transit status of the goods is a live fact that must travel with whatever happens next, and the TAD and MRN are how the movement is identified to customs. The driver briefing is therefore simple and worth saying out loud: goods under transit are not ordinary freight; the paperwork is part of the load; and any incident on a transit movement gets reported upward immediately, because somewhere a guarantee is standing behind the duty that has not yet been paid.