A new row broke out between the European Union and the UK after the British government said it would unilaterally extend the grace period for checks on food going to Northern Ireland. The EU said the move breaks international law, while France and Ireland also denounced the plan. Northern Ireland remains part of the bloc’s single market for produce arriving from mainland Britain, with goods required to undergo EU import procedures. Extending the grace period would exempt goods, such as food, medicine and plants, from border checks. The province remained in the single market to avoid creating a hard border on the island of Ireland, which could jeopardise the peace process under the 1998 Good Friday Agreement. Northern Ireland Secretary Brandon Lewis sparked the new dispute by announcing that the grace period would be extended from April until October 1. The UK government called the six-month delay a “limited and technical” arrangement and said it was necessary "to provide more time for businesses, such as supermarkets and parcel operators, to adapt to and implement the new requirements”. EU vice-president Maros Sefcovic said it was a violation of part of the Brexit deal known as the Northern Ireland protocol and that the bloc would respond within the "legal means" established under the agreement. "This is the second time that the UK government is set to breach international law," he said, referring to a previous, unsuccessful attempt by London to override the protocol. Mr Sefcovic said the agreement aimed to protect the treaty that helped to bring an end to decades of sectarian violence in Northern Ireland. Irish Foreign Minister Simon Coveney said the extension "clearly undermined" the UK’s commitment to the Northern Ireland protocol. "A unilateral announcement is deeply unhelpful to building the relationship of trust and partnership that is central to the implementation of the protocol," he said. France's European Affairs Minister Clement Beaune said the move was "obviously illegal and unacceptable". It was initially agreed that the grace period would end in April to allow Northern Ireland’s shops time to establish new supply chains. Supermarket shelves in the province were largely bare in the first weeks of the year, after the post-Brexit transition period ended and Britain left the EU single market on January 1, as some UK suppliers refused to ship goods across the Irish Sea. The border checks on goods arriving from Britain sparked protests among pro-UK unionists in Northern Ireland, who warned of rising tension in their communities over the protocol. Prime Minister Boris Johnson said on Wednesday that Northern Ireland's place within the UK internal market was "rock solid and guaranteed". He spoke of "some temporary operational easings in order to protect the market in some areas, such as food supplies, pending further discussions with the EU".