Border checks 'unavoidable' if Britain leaves customs union
The Border problem is back, with the EU's leading Brexit negotiator warning that checks will be "unavoidable" if the UK leaves both the single market and customs union.
Despite Taoiseach Leo Varadkar insisting that December's deal on the Border was "bullet- proof" and "cast-iron", the spectre of a hard Border remains, with Brussels saying the UK has failed to come up with any solutions.
European Commission chief negotiator Michel Barnier also starkly warned that the transition period could be in doubt, amid substantial disagreements between London and Brussels, sending sterling weaker.
"It is important to tell the truth. A UK decision to leave the single market and to leave the customs union would make Border checks unavoidable," Mr Barnier said.
The atmosphere has soured since Brussels published a position paper that included a plan to restrict access to the single market, if the UK fails to comply with the terms of the transition.
The startling developments come despite the deal struck in December between the EU and UK.
At the time, the Government here was triumphantly stressing that this would avoid the return to a hard Border.
The objective of that deal is to reach a new UK-EU relationship - but if this doesn't occur, then the UK will come up with specific solutions.
A final element was added at the request of the Irish Government, which essentially states that if no final deal can be done, the UK will maintain "full alignment" with the EU rules required to ensure that north-south co-operation in terms of trade, regulations and standards, can continue.
But two months on, and a clearly frustrated Mr Barnier said the UK had yet to table solutions that would avoid a hard Border.
He said any solution must be "precise, clear and unambiguous".
Mr Barnier said the commitment to maintain full regulatory alignment must now be written into the legally-binding withdrawal agreement "to guarantee that there will be no hard Border whatever the circumstances".
"This means that we must now start legally defining how this scenario would work in operational terms.
"There must be no ambiguity here.
"Based on the discussions this week, the UK has accepted the necessity of discussing how to make this full alignment scenario operational, provided we discuss the other two options in parallel.
"This is what we will work on in the coming rounds."
Mr Barnier yesterday outlined the three options for ensuring no obstructive physical borders on the island of Ireland, as per the wording of the December agreement.
First, through a newly negotiated EU-UK relationship; or second through alternative solutions - although these have yet to be put forward by the UK.
Failing those, the third fallback option of regulatory alignment in the event of no deal.
That third option - which Mr Barnier said now needed to be legally enshrined in the exit agreement - has the potential to complicate the UK's ability to trade with countries that have different standards to the EU.
An added problem is that there is so far no agreement on what rules should be aligned. Brexit Secretary David Davis (pictured inset) hit back at Mr Barnier in a stinging statement.
He said: "Given the intense work that has taken place this week it is surprising to hear that Michel Barnier is unclear on the UK's position in relation to the implementation period.
"As I set out in a speech two weeks ago, we are seeking a time-limited period that maintains access to each other's markets on existing terms.
"However, for any such period to work both sides will need a way to resolve disputes in the unlikely event that they occur."