Ireland’s finance minister warned that the country’s government remains “highly skeptical” about proposals advocated by Britain’s prime minister to avoid the need for infrastructure on the U.K.’s border with Ireland after Brexit.U.K. premier Boris Johnson had visited Dublin Monday for talks with his Irish counterpart, Leo Varadkar, and insisted that trusted trader schemes and electronic pre-clearances of goods were areas in which there was “a lot that can be done” to resolve a problem that bedevilled his predecessor Theresa May: how to reconcile an open border between the Republic of Ireland and the U.K., while allowing Britain to strike independent trade deals in the future.But Varadkar’s finance minister Paschal Donohoe, speaking to CNBC at Ireland’s U.K. embassy after a day of investor meetings in the City of London, argued that the British leader’s suggestions do not respond to the “unique needs of the Irish border,” and that was why the Irish government has “stood so firmly behind the principle of regulatory alignment, and the backstop.”The so-called “Irish backstop” forms an element of Theresa May’s negotiated exit deal with Brussels, and is designed to protect the continued openness of the border between the Republic of Ireland in the south and the separate nation, Northern Ireland, that forms part of the United Kingdom, in case further talks between the U.K. and EU do not find a long-term, operable resolution to the issue.The open border and freedom of movement between the two countries were key tenets of a 1998 peace deal that heralded the end of ongoing violence in the region.The backstopBut the European Union’s rules that are designed to protect the integrity of its single market do not allow for goods, services or people to travel frictionlessly into its territory outside the framework of a trade agreement. The regulatory requirements contained in those kinds of agreements can make it difficult for a third country like the U.K., under such a regime, to operate the kind of fully independent trade policy that the current British leader considers a crucial benefit to be derived from Brexit.To make that possible, the U.K. would typically need goods to be checked at Britain’s frontier with Europe. But Johnson in Dublin insisted this was not an acceptable consequence.”The U.K. will never, ever institute checks at the border, and I hope our friends in the EU would say the same,” Johnson told Varadkar.But the British leader has said previously he is confident about his ability to win from EU leaders certain concessions that might avoid the need for the contentious insurance policy altogether. He has vowed the U.K. will then be able to discard — or “bin” — the backstop, which was a major reason many lawmakers in his Conservative Party previously refused to endorse May’s deal in three separate parliamentary votes.Johnson voted against the deal twice before voting for it on the third occasion.The current prime minister’s critics say his government has failed to provide specific alternatives to the Irish backstop in the weeks since he took office. And speaking outside the Irish leader’s residence Farmleigh House on Monday morning, Johnson continued to be coy about the particulars.”There are an abundance of proposals that we have, but I don’t think it’s entirely reasonable to share them with you today,” he told assembled journalists.In response Donohoe, during his interview with CNBC, backed Varadkar’s earlier stated position that Ireland was not prepared to “replace a legal guarantee with a promise.”The finance chief said the Irish would listen to new proposals, but these kinds of alternative arrangements had been previously examined and found wanting.”If anyone does believe that there are ideas that could take the place of the backstop then of course we are open to engaging with those ideas.”Donohoe reiterated an oft-stated Irish government view that if proponents of the “alternative arrangements” Johnson mentioned Monday were so confident in their operability, then they should first ratify the backstop and the withdrawal agreement, then push for them during that transition period, rather than risk the entire agreement by insisting on them now.Theresa May’s withdrawal agreement negotiated with the EU had included a lengthy transition period during which the U.K. would continue to operate under EU rules. The intention of negotiators on both sides was for that period to offer businesses some continuity and to provide the U.K. and Irish governments more time to find workable solutions to the border challenges.British politicians in favor of a swift Brexit dislike the idea that the U.K. will have to abide by EU rules after Brexit, and could be forced to rely too heavily on European goodwill to allow the introduction of new arrangements that would automatically render the backstop unnecessary.But internal government documents leaked to the website Politico earlier this month and written by U.K. technical advisory groups tasked with examining “alternative arrangements” to the Irish backstop found that “trusted trader schemes” — whereby firms get pre-approval to move goods back and forth across the border without checks — had proven to be a “popular facilitation” among surveyed businesses, but would likely still require some form of border infrastructure in order to work.The same government technical advisors acknowledged there were various options that might address individual challenges stemming from the border’s necessarily open status, but that “every facilitation has concerns and issues” and that the “complexity of combining them into something more systemic and as part of one package is a key missing factor at present.”British Prime Minister Boris Johnson welcomes Israeli Prime Minister Benjamin Netanyahu (not pictured) outside 10 Downing Street ahead of bilateral talks on 05 September 2019 in London, England.WIktor Szymanowicz | NurPhoto | Getty ImagesOne solution that Irish and European government officials posited in the past would have required Northern Ireland to submit to a different regulatory environment to the rest of the U.K.; a backstop specific to Northern Ireland alone. But Theresa May’s government had categorically refused to allow this because of its implications for U.K. unity, and had negotiated hard to make the backstop applicable to the entire U.K. in the face of fierce EU opposition.May had relied on votes from a small Northern Irish political party, the Democratic Unionists, to maintain a parliamentary majority after she lost ground in a 2017 election. But Johnson no longer enjoys that majority, and lost six out of six parliamentary votes in the past week before the legislature was suspended for five weeks on Monday night.Some senior government ministers have hinted publicly that a backstop that only applies to Northern Ireland may now be the best option left open to Downing Street, if Johnson is to fulfil his promise of leaving the world’s largest trading bloc by Oct. 31.