Some steel exports from Great Britain to Northern Ireland are facing a 25% tariff because of changes to EU rules.

HM Revenue and Customs told steel producers of the tariff on Wednesday.

The tariff is related to the Northern Ireland Protocol, the post-Brexit deal which means Northern Ireland is continuing to follow EU customs rules.

The EU has changed some of its rules in regard to steel imports for reasons related to Russia's invasion of Ukraine.

That has had a knock-on effect on steel sales from Great Britain to Northern Ireland.

Trade expert Sam Lowe set out the complicated background to the issue earlier this month.

Essentially, steel from Great Britain had been able to enter Northern Ireland without a tariff because it was covered by a tariff rate quota (TRQ) for UK exports to the EU.

A TRQ allows a certain amount of a product to enter a customs territory without a tariff being paid, but once a set limit is reached tariffs apply.

Until June there was a specific TRQ for UK steel exports to the EU.

However, when sanctions were applied to Russia EU businesses could no longer buy steel from there.

So at that time the EU scrapped country-specific TRQs for the UK and others in favour of one TRQ for Ukraine and another TRQ covering all "other countries".