Holding answer received on 14 March 2019
The terms of the European University Institute Convention (EUIC) expressly refer to the contracting states of the Convention being EU Member States and limit future accession to the Convention to EU Member States. It is therefore not possible for a non-Member State to become a signatory to the Convention and participate in that capacity. Accordingly, when the UK ceases to be a Member State of the EU, it will also cease to be a party to the Convention. However the UK will continue to be covered by the EUIC for the duration of the Implementation Period if the Withdrawal Agreement is passed.