The EU's chief Brexit negotiator Michel Barnier said Britain must accept the new realities of Brexit, and it was the UK withdrawal from the EU that led to the tensions between London and Brussels over Northern Ireland, not the Brexit protocols, Reuters reported.

The UK has pushed for changes to the Brexit protocol for Northern Ireland after the European Commission tried to prevent the movement of vaccines across the open border between EU Ireland and Northern Ireland.

According to him, both sides must realize their responsibility for the full application of this protocol. 

The difficulties on the island of Ireland are caused by Brexit, not by protocol, he added.

Slightly less than half of UK exporting companies have faced issues stemming from a shift in the terms of trade with the EU since the beginning of the year, a poll released Thursday showed.

It is clear that there will be a period of adaptation, Barnier said.

Despite a trade agreement free of duties and quotas, the business faces barriers such as new paperwork and veterinary checks.