'Irish border issue' must be settled before Brexit talks, says next EU president Joseph Muscat
The "Irish border issue" must be settled before talks on Brexit can begin, the next EU president has told the BBC.
Malta's Prime Minister Joseph Muscat made his comments as a British-Irish council meeting was being held in Wales.
In a BBC interview he said: "There will be issued relating to borders, especially the Irish issue, which I think is one of the most politically sensitive issues that I think there is a political willingness from everyone to have it resolved."
Meanwhile devolved leaders have challenged the Prime Minister on why she stayed away from the Brexit-themed summit that focused on regional concerns around free trade.
Scotland's First Minister Nicola Sturgeon and Northern Ireland's Deputy First Minister Martin McGuinness said Theresa May should have attended the British Irish Council (BIC) meeting in Wales.
The event, near Cardiff, brought together the leaders of the UK's three devolved administrations, a number of UK Government ministers, Irish premier Enda Kenny and the first ministers of the Crown dependencies.
Top of the agenda was how the UK could maintain access to the European Single Market post-Brexit if it denied freedom of movement to EU citizens.
BIC summits are held twice a year. UK prime ministers have attended in the past, but not on a regular basis.
Sinn Fein veteran Mr McGuinness said the context of Friday's event should have prompted Mrs May to take part.
"I think the British Prime Minister should have been here today," he said.
"She is a new British Prime Minister, this was her first opportunity to attend the meeting of the British Irish Council and to meet with the devolved institutions and the Crown dependencies and I think it was a missed opportunity on her behalf."
During the post-summit press conference, Mrs Sturgeon echoed Mr McGuinness's remarks.
"I agree strongly with that," she said.
Four UK Government ministers did attend the discussions at the Vale Resort, but no senior Cabinet members were among them.
Those who partook were Welsh Secretary Alun Cairns; Northern Ireland Secretary James Brokenshire; Parliamentary Under Secretary at the Department for Exiting the European Union Robin Walker; and Parliamentary Under Secretary of State for Women, Equalities and Early Years Caroline Dinenage.
When asked if Mrs May should have be there, Mr Brokenshire said: "The Prime Minister strongly supports the British Irish Council, that's why you had two Cabinet ministers and two other ministers here today strongly representing the UK government's perspective."
The summit took place in the wake of comments by Malta's Prime Minister Joseph Muscat making clear that unfettered single market access could not be offered if it was not accompanied by free movement. Malta will assume the six-month rolling presidency of the EU in January.
Ahead of the BIC meeting, host Welsh First Minister Carwyn Jones stressed the importance of free trade with Europe, particularly in the context of potentially protectionist policies from a Donald Trump White House.
After the summit, Mr Jones said there was a need for "creativity" and the single market versus ending free movement could not be a binary one or the other.
"We take the view that access to the single market is the most important issue and I don't think it is practical to say that it is possible to have full border control, as it's put, and access to the single market at the same time - there needs to be compromise and there needs to be balance and these are the challenges that will be faced as the negotiation moves forward."
Stormont's First Minister Arlene Foster, who as leader of the Democratic Unionists campaigned for Brexit, also said the outcome did not have to be binary.
"Do I think it's binary - no I don't think it's binary, because negotiations are about coming to accommodations," she said.
"What we need to see is an openness and a willingness to do what is right for each of the constituent parts of the United Kingdom."
Mrs Sturgeon said the UK Government needed to provide much more clarity on the issue before Article 50 of the Lisbon Treaty was triggered to commence the Brexit process.
The SNP leader again made clear her desire for Scotland to continue to be part of the single market, even if the rest of the UK left it.
She said the prospect of a "hard" Brexit with the UK leaving the single market was a real possibility.
"From the perspective of the Scottish Government of course we are looking at, if those circumstances arise, how could we best protect our own interest, protect our place in the single market, even if the UK decides to leave," said Mrs Sturgeon.
"Of course that would be challenging, there would be a number of practical barriers that we would have to overcome and the work we are doing right now is to explore how those barriers could be overcome."
Mr Kenny raised concerns from the Irish Republic's perspective about the potential of border checks and trade tariffs.
"I didn't like the decision of the UK electorate but I respect it and we now have to deal with it," he said.
"The best outcome would be something as close to what we have at the moment. I think everybody will agree that the importance of the single market is critical for everybody."
Mr Brokenshire said the UK Government was analysing different options to balance the need for fluid trade and reflect the electorate's desire for limits on immigration.
"We don't see it as a binary choice, we do see different options," he said.
"We are considering those options carefully as we look to the triggering of Article 50 and establishing that UK-wide stance, so we do get the best possible arrangement for all parts of the United Kingdom. And it is that arrangement we are pursuing."
The BIC was established as part of the 1998 Good Friday peace agreement in Northern Ireland.
Its aim is to promote links between the UK's devolved regions, the Irish Republic, the Isle of Man, Jersey and Guernsey.
Its membership comprises representatives from the Irish Government; UK Government; Scottish Government; Northern Ireland Executive; Welsh Government; Isle of Man Government; Government of Jersey and Government of Guernsey.
The chief ministers of the Isle of Man, Jersey and Guernsey - Howard Quayle, Ian Gorst and Gavin St Pier - also attended Friday's summit along with ministerial colleagues from their respective administrations.