The EU's chief Brexit negotiator Michel Barnier has said the EU will remain "vigilant" in monitoring the development of infrastructure, logistics and human resources in how the UK prepares to implement the checks and controls on the Irish Sea, as set out in the Protocol on Northern Ireland.
At a news conference in Brussels Mr Barnier repeatedly linked the implementation of the Protocol to the issues of trust, and the ongoing negotiations to forge a future relationship between the EU and UK.
He took aim at the new Northern Ireland Secretary Brandon Lewis, saying he had said some "surprising" things, and invited him to read the detail of the Withdrawal Agreement in terms of commitments both sides had entered into.
Mr Lewis has said on a number of occasions that there would not be a border on the Irish Sea.
The Protocol on Northern Ireland/Ireland, however, requires checks and controls on goods moving from Great Britain to Northern Ireland by the end of this year.
Mr Barnier said, however, that the issue should be "de-dramatized", saying there were already checks on live animals entering Northern Ireland from Great Britain.
Mr Barnier was speaking after the EU adopted its negotiating mandate to begin talks next week.
He told reporters that the Joint Committee, tasked with implementing the Protocol, would hold its first meeting later in March.
The former Slovak diplomat and current Vice-President of the European Commission Maroš Šefčovič would be the EU's representative on the Joint Committee, he confirmed.
Mr Barnier said he would take stock of how far the UK had implemented the new system of checks and controls by the beginning of the summer.
He said infastructure was just one of a number of benchmarks he would be looking at.
Earlier this morning, following a meeting with Mr Barnier, the Tanaiste Simon Coveney said: "If there isn't progress on the infrastructure needed to implement the Irish protocol as part of the Withdrawal Agreement in the next few months, then I think that is going to be a very worrying signal for whether or not it's going to be possible to conclude something sensible before the end of the year."