Cross-border VAT in Northern Ireland: the plain-English guide

Under the Windsor Framework, Northern Ireland stays aligned with EU VAT and customs rules for goods, while following UK rules for services. Everything else follows from that split.

The practical consequence is that two NI businesses can be doing what looks like the same transaction — selling to a customer in Dublin — and face entirely different treatment, because one sells physical product and the other sells consultancy. If you sell both, you're running two sets of rules at once.

Four thresholds decide most cross-border VAT questions for Northern Ireland businesses:

Irish VAT rates matter too when you are pricing: the standard rate in the Republic is 23%, against 20% in the UK. Quote a consumer price across the border without adjusting for that three-point gap and it comes straight out of your margin.

Because NI remains aligned with EU rules for goods, movements from Northern Ireland into the Republic and onward into the EU are not treated as exports to a third country the way a GB business's would be. For many NI businesses this is a genuine commercial advantage.

Three conditions have to be met to zero-rate a business-to-business supply of goods from NI to an EU customer. The customer must be VAT registered in an EU member state and must have given you that VAT number. The goods must actually be sent or transported out of Northern Ireland to a destination in that member state. And you must submit an EC Sales List accounting for the supply.

You also need evidence that the goods moved, and HMRC sets time limits on getting it: three months for a standard supply, six months where the goods are being processed or incorporated into something else before dispatch, and two months for a new means of transport. Miss the window and the zero rate falls away even though the sale itself was perfectly legitimate. That evidence requirement is where businesses come unstuck — the treatment can be right and the claim still fail because nobody kept the proof.

One piece of administration is easy to miss. NI businesses selling goods to the EU need to use the XI prefix on their VAT number when dealing with EU customers and suppliers — XI 123456789 rather than GB 123456789 — on invoices and in correspondence. Your customer's accounts team validates that number before they will accept a zero-rated invoice. Send it with a GB prefix and the invoice comes back.

Buying goods from a supplier in the Republic or elsewhere in the EU is an acquisition rather than an import. You account for acquisition tax at the UK rate that would apply to those goods, and recover it as input tax under the normal rules — so for most VAT-registered businesses buying standard-rated stock, it nets to nothing but still has to appear on the return. The tax point is the earlier of the 15th day of the month following dispatch, or the date the supplier issued their invoice, which is worth knowing when a delivery straddles a quarter end.

Movements from GB into NI sit within the same UK VAT system, but the customs and declaration position is separate and depends on where the goods ultimately end up.

The mechanism to know about is the UK Internal Market Scheme. Authorisation under it lets you declare goods brought into Northern Ireland as "not at risk" of moving into the EU — meaning they are for sale to or final use by end consumers in the UK — and gives you access to the Simplified Processes for Internal Market Movements. That simplified route uses a much smaller dataset than a full customs declaration, and no duty is charged on goods arriving from free circulation in Great Britain. You need the authorisation in place before the goods move, which is the single most common reason a business ends up paying for a workaround it did not need.

If you bring goods in from GB regularly, settle three questions once: whether you need an EORI number, which of your movements need declarations, and what records you have to keep and for how long.

Services follow UK rules regardless of where your customer is. The general business-to-business rule places the supply where the customer belongs, so a service supplied to a business customer in the Republic is generally outside the scope of UK VAT, with the customer accounting for it under the reverse charge.

There are exceptions — land-related services, admission to events and a few others follow different rules. But if you sell services only, none of the goods complexity above applies to you.

1. Treating NI as GB for goods. The most common and the most expensive.

2. Applying the goods answer to a services business. The reverse error — worrying about customs and EORI numbers when you sell consultancy.

3. No evidence of movement. Keep the transport documents.

4. Inconsistent currency handling. Not strictly VAT, but it distorts margins and it almost always travels with cross-border trade.

5. Assuming an Irish VAT registration is needed — or that it isn't. Both errors happen, and both cost money.

The figures below are illustrative, chosen to show the mechanics rather than to describe any particular business. Take a Ballymena food producer turning over £600,000 a year, split three ways.

• £420,000 to customers in Great Britain. Ordinary UK VAT, standard rated at 20% where the product is not zero-rated food.
• £120,000 of goods to a VAT-registered distributor in Dublin. Zero-rated, provided the three conditions above are met: the Irish VAT number obtained and shown on the invoice, evidence of removal held inside three months, and an EC Sales List submitted. Because the £120,000 of EU goods sales is well over £35,000, that EC Sales List is due monthly rather than quarterly.
• £60,000, net of VAT, sold direct to consumers in the Republic through the website. This is the one that goes wrong. Consumer sales are over the €10,000 EU-wide distance selling threshold, so Irish VAT at 23% is due — roughly £13,800 a year — either through an Irish VAT registration or through a single quarterly One Stop Shop return covering every EU country at once.

Now the expensive version. Suppose the producer treats that third stream as ordinary UK sales and charges 20%. It hands HMRC around £12,000 that was never due, while still owing Irish Revenue roughly £13,800 that it never collected from customers — because the price it quoted was built on 20%. The exposure is both at once, plus interest, on a mistake that repeats quietly every month until someone looks. Registering for OSS is a single administrative step that removes it.