The only solution to Ireland's Brexit border row with Britain is to introduce technology to manage multinational trade while turning a blind eye to lower-level cross-frontier movement, former taoiseach Bertie Ahern has suggested.
The issue of how to maintain the "soft" border between Northern Ireland and the Republic of Ireland after Brexit is a key stumbling block in Brexit negotiations, and British Prime Minister Theresa May has just a week to meet a European deadline to make progress before trade talks can begin.
Cabinet minister Liam Fox has said the issue cannot be resolved until it is known what the "end state" of the UK-EU trade relationship will be after Brexit 2019, but Dublin has called for firm guarantees amid fears that the Government's commitment to leaving the single market and customs union could see a return to a hard border.
Mr Ahern said the only option appeared to be using technology to manage a soft border governing EU-UK trade between Ireland and Northern Ireland, while simply ignoring lower level commerce in areas like agriculture.
"Our economy is relatively small, a huge amount of the trade is multinationals; it should be possible, I think, to do that by technology," he told BBC Radio 4's Today programme.
"But of course, when you come down to agriculture and smaller items, I don't think technology would work.
"One thing we do not want, can't have, is back to a physical border."
He added: "Theresa May, take her at her word, she's confidently said she doesn't want a physical border, the EU don't want a physical border, the Irish government don't.
"So you're left down with the one alternative - to make technology work in most cases and to throw a blind eye to those areas that can't come in within technology."
Mrs May has been given until December 4 to come up with further proposals on issues including the border, the Brexit divorce bill and citizens' rights if European leaders are to give the green light to moving on to the next phase of negotiations covering the future trading relationship between the UK and Brussels.
As talks on the first phase reach a crunch point, Ireland's Foreign Affairs Minister, Simon Coveney, has insisted his country must be protected from the Brexit process and dismissed a claim from Ukip that Dublin was threatening the UK.
He said: "Ireland is not threatening anybody, least of all a friend, but we remain resolute in our insistence on a sensible way through Brexit that protects Ireland."
Dublin has said that if either the whole of the UK or just Northern Ireland remains in the single market and customs union then there would be no problem with maintaining the current soft border arrangements - a proposal ruled out by the prime minister.
International Trade Secretary Dr Fox said: "We don't want there to be a hard border but the UK is going to be leaving the customs union and the single market."
He added on Sky News's Sunday with Niall Paterson: "We can't come to a final answer to the Irish question until we get an idea of the end state."
Irish senator Neale Richmond, a European affairs spokesman for the Fine Gael party that leads the government, warned of violence if there is a return to a hard border.
He told Today: "There is paramilitary and criminal activity on both sides of the border at the moment, and indeed from both communities, and I come from an Irish community myself.
"So to simply say that there's no threat ... there is a threat, the PSNI and An Garda Siochana have said there is a viable paramilitary threat to the peace process.
"You put up one watchtower, or put out one customs patrol, and they will be a target, and I would argue they would be attacked within a week of them going up."
Irish European Affairs Minister Helen McEntee has acknowledged that some of the final details would have to be dealt with in the next phase of Brexit talks but the UK must come forward with further proposals now to achieve the aim of maintaining a soft border.
Moving on to phase two of the negotiations, on trade, can only happen if all 27 leaders of the remaining EU countries agree at the European Council summit on December 14-15 that "sufficient progress" has been made on the first set of issues.
Any arrangement which appeared to give Northern Ireland a separate status would be strongly resisted by the DUP, whose 10 MPs are effectively keeping Mrs May in Downing Street after she lost her majority in the general election.
The European Parliament's Brexit co-ordinator Guy Verhofstadt suggested that more work also needs to be done on the issue of the post-Brexit rights of EU citizens living in the UK and Britons living on the continent.
Alongside the Irish border and the UK's exit bill, citizens' rights is one of the three "divorce" issues which the EU wants to settle in the first phase of talks before moving on to trade.
In a message on Twitter, Mr Verhofstadt said: "The European Parliament still has a number of outstanding concerns over citizens' rights, which I hope can still be solved in the coming weeks.
"Brexiteers promised that people would be able to continue their lives as before - now it's time to deliver."
