Customs procedures at the border are an inevitable outcome from Brexit, according to the EU’s agriculture and rural affairs policy body DG Agri. The UK’s intention to leave both the single market and the customs union means there will have to be customs checks at the border.“The UK is leaving the EU. It will become a third country from March 2019. This is a fact,” said Brigitte Misonne, deputy head of DG Agri’s animal unit.