Commercial Invoice for Exports to the UK: Mandatory Fields, KSeF and 0% VAT

Exporting goods from Poland to the United Kingdom requires not only a customs declaration, but also a correctly issued commercial invoice. Errors in the document — a missing HS code, the wrong currency, or no EORI number — can hold up the goods at the border or cost the company the right to the 0% VAT rate. This article is for exporters, sales teams and accounting departments handling PL→UK transactions.

What is a commercial invoice and how does it differ from a VAT invoice?

The commercial invoice is the basic document accompanying an export shipment — required by the customs authority on both the PL side (AES/PUESC export declaration) and the UK side (CDS import clearance). It does not replace a VAT invoice, but exporters often combine both documents — provided it contains all the required fields.

After Brexit, the UK is a third country: every shipment from Poland to England, Scotland or Wales is subject to the full export (PL) and import (UK) procedure.

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Mandatory fields on a PL→UK commercial invoice

The HS code — a key field

The HS code is the basis on which HMRC calculates duty. Poland uses the 8-digit CN, while the UK has its own 10-digit tariff (the UK Global Tariff). The correct code allows the importer to lodge a correct CDS declaration. Check the code: UK Trade Tariff — Find a commodity.

EORI — both numbers current

The exporter must hold a PL EORI number (KAS, free, applied for via PUESC). The buyer in the UK needs a GB EORI number (HMRC, free). Without a GB EORI number, the importer cannot lodge a CDS declaration, so the goods will be held. GB EORI registration is described at gov.uk/eori.

Incoterms — the effect on customs value

Incoterms 2020 determine who bears the costs and risk. Customs value in the UK is based on the transaction value plus the cost of transport and insurance up to the point of entry into the UK (see customs value and DDP mistakes). Enter the full term and place, e.g. CIF Felixstowe or DAP London; the differences are explained in Incoterms EXW, FCA and DAP explained.

0% VAT on exports — documentary conditions

Exports of goods are subject to a 0% VAT rate (Article 41(4) of the Polish VAT Act). The condition is receiving a document confirming that the goods left the territory of the EU before the deadline for filing the return for the given period (Article 41(6)). Such a document includes an electronic document from the export declaration system, or a printout confirmed by the customs authority (Article 41(6a)).

The IE599 message (CC599C)

IE599 is the electronic message from the export system confirming that the goods have left the EU customs territory. It is the main document on which the 0% rate rests. It appears once the export is completed and can be retrieved through the export declaration system (PUESC) or via your agent.

IE529 — a temporary document

IE529 confirms that the export procedure has started (the declaration has been accepted). If you do not yet have the document confirming export by the return deadline but hold a customs document confirming the export procedure, you can report the export in the following period at 0%, provided you receive the confirmation of export before the deadline for the return for that following period (Article 41(7) and (8)). If you do not receive it, the rate applicable to a domestic supply applies. Receiving the document later lets you correct the output tax in the return for the period in which you received it (Article 41(9)).

KSeF and export invoices — status as of October 2026

The National e-Invoice System (KSeF) is a system for issuing structured e-invoices through the Ministry of Finance platform. The obligation to issue invoices in KSeF came into force in two stages and now applies to all active VAT payers established in Poland.

Important: The phased deadlines were introduced by the Act of 5 August 2025 (Journal of Laws 2025, item 1203). Until the end of 2026, transitional simplifications apply, e.g. for taxpayers with monthly sales of up to PLN 10,000 (invoices outside KSeF). KSeF rules are amended from time to time — always check the current status at ksef.podatki.gov.pl.

The KSeF obligation covers invoices issued by VAT payers established in Poland, including those for foreign buyers; the Act excludes, among others, invoices to private individuals not running a business (Article 106ga(2) of the VAT Act). A buyer outside Poland does not use KSeF, so the structured invoice is made available to them in a manner agreed with them (Article 106gb(4)) - in practice as a PDF or printout with the KSeF number and QR code, which you can pass to your customs agent and the UK importer.

Common mistakes

1. Missing HS code or incorrect classification — the goods are held, the UK declaration has to be corrected.
2. No buyer (GB) EORI number — the importer cannot lodge a CDS declaration; storage costs are incurred.
3. Undervalued goods / no Incoterms — HMRC may challenge the customs value.
4. Mismatch between the invoice description and the EX declaration — risk of the 0% VAT rate being refused.
5. No confirmation of export (IE599) within the deadline — once the deadlines under Article 41(6)-(7) pass, the domestic rate applies and you correct the tax after receiving the document.
6. Inconsistent consignor and consignee details — the name, address and contact details on the invoice should match the data used for clearance; a mismatch increases the risk of queries and delays.
7. Invoice, packing list and transport order that do not match — the quantity and weight data in these documents should match.
8. A description of the goods that is too general — "parts", "goods" or "samples" do not let the goods be matched to a classification, and general terms such as "parts" are not accepted in a CDS declaration; say what the goods are and what they are used for.
9. Invoice submitted for checking too late — corrections made just before departure cost the most time, so send the document for review before the transport starts.

How we can help

At Agencja Celna (agencjacelna.uk) we handle PL↔UK export and import: preparing and checking commercial invoices, EX export declarations in PUESC, PL and GB EORI numbers, tariff classification (HS codes), and UK import clearance (CDS). Get in touch before your first shipment via the contact form, or read who is responsible for clearance when exporting to the UK.

Sources

• KSeF — legal basis and deadlines (ksef.podatki.gov.pl)
• UK Trade Tariff — Find a commodity
• EORI GB — registration (gov.uk/eori)
• PUESC
• business.gov.uk: how to create an export invoice
• HMRC: CDS import declaration completion instructions, goods description (DE 6/8)
• Polish VAT Act (Journal of Laws 2026, item 1263)

Frequently asked questions