Ireland: Inward Processing is a customs special procedure. It permits authorisation holders to delay or reduce import duties or VAT on non-EU goods for processing or repair. Excise duty may also be suspended. Further advice is available from Irish Revenue.
The export side of this procedure is called Outward Processing. It permits temporarily exporting of EU goods for processing/repair in non-EU countries. More information is available from Irish Revenue.
Northern Ireland: Inward Processing enables authorisation holders to delay or reduce import duties or VAT on goods for processing or repair. Excise duty may also be suspended. The UK government advises that traders applying for authorisation in Northern Ireland and GB need to complete a separate application for each. Traders carrying out work at locations in both Northern Ireland and the EU, can get a single authorisation rather than having one for each place. The export side of this procedure is called Outward Processing.
GOV.UK have further advice on Inward Processing and Outward Processing.
Read our comprehensive guide to trade routes and customs paperwork article with lots more information, important actions businesses need to take and links to further support.