The European Union has accused the British government of breaching international law as it made a move to extend the grace period for Irish border checks.

Northern Ireland has remained part of the EU’s single market, meaning goods arriving at its ports from Great Britain undergo EU checks and procedures.

To allow Northern Irish businesses time to adapt to these new regulations, a grace period was in place that is due to end at the end of March, but British ministers have said they will extend it until October.

In a statement, European Commission vice president Maroš Šefčovič said this decision from the UK government was “a violation of the relevant substantive provisions” of the Brexit deal on Northern Ireland, known as the Northern Ireland protocol.

The grace period largely affects supermarkets and other retailers that would have had to produce export health certificates for all shipments of animal products from the end of the month, as per EU regulations.

The UK government has defended the decision as operationally necessary.

It said in a statement: “For supermarkets and their suppliers, as part of the operational plan the UK committed to at the UK-EU Joint Committee on February 24, the current Scheme for Temporary Agri-food Movements to Northern Ireland will continue until October 1.

“Certification requirements will then be introduced in phases alongside the roll-out of the Digital Assistance Scheme.”