Jeremy Hunt was confronted over alleged British attempts to isolate Ireland from its EU partners by the country’s deputy prime minister during a meeting in Brussels on Monday, as tensions over the continuing Brexit impasse bubbled to the surface.

Ireland’s tánaiste, Simon Coveney raised “negative briefings” in a private meeting with the foreign secretary before later publicly expressing his frustration over a lack of progress, with fewer than 40 days to go until Brexit.

Warning that Ireland would not be “steamrolled” in the last weeks of the Brexit talks, Coveney told reporters: “Yes, there is frustration in Ireland. We have less than 40 days to go to until the United Kingdom is formally leaving the European Union and we still don’t know what the British government is actually asking for to actually get this deal ratified. So, yes, there is frustration.”

When asked by reporters about the clash with the British cabinet minister, Coveney said there had been a “good and honest” discussion but that he would not publicly “start slinging accusations around the place”.

Ireland has become concerned by perceived attempts by the British government to depict Irish intransigence over the backstop as the only stumbling block to ratification of the Brexit deal by parliament.

Ireland's deputy PM on backstop: 'We will not be threatened' Read more

Coveney, who held meetings with both the EU’s chief negotiator, Michel Barnier, and Hunt in Brussels on Monday, called for Downing Street to bring “some sense” to the negotiations.

He reiterated the EU line that the bloc would not renegotiate the backstop, which could keep the UK in a customs union to avoid a border on the island of Ireland.

Coveney added that Ireland would neither accept a time limit or its replacement with an alternative arrangement, such as a technological solution, which he said would leave peace in Northern Ireland relying on “wishful thinking”.

Play Video 20:10 Brexit breakdown: fear and anger on the Irish border – video

“I think the asks of the British parliament and the British government have to be reasonable ones,” he said. “What we can’t do is essentially remove or change the guarantee and the insurance ... that prevents border infrastructure in the future and replace it with something that is wishful thinking rather than something that is tested.

“We can’t either support a time limit to the backstop because – unless you can answer the question what happens after that set period of time – we are just kicking the issue further down the road without answers.

“A backstop with a set time limit isn’t a backstop at all. We all want it to be temporary but it has to be replaced by something that is credible and tested.”

Brexit must not endanger the Good Friday agreement | Simon Coveney Read more

The comments came as the Brexit secretary, Stephen Barclay, and the attorney general, Geoffrey Cox, also held talks with Barnier over the UK’s demands for a reopening of the withdrawal agreement.

Following the meeting, Barclay said he would meet Barnier again on Wednesday over a “legal way forward”. The two negotiating teams are seeking a solution that will allow Cox, to change his advice that the Irish backstop is “indefinite” to being temporary.

He said: “The attorney general shared his thinking in terms of the legal way forward and how we address the central issue of concern signalled in the Brady amendment in terms of having an outcome that addresses … the indefinite nature of the backstop. We agreed a next step forward so we’ll be engaging again midweek.”

The British prime minister has insisted that she needs a time-limit to the backstop, a unilateral exit mechanism or its replacement with alternative arrangements to get her deal through the Commons.

Coveney said a no-deal Brexit would be a “crazy” outcome but that there was “no appetite” for renegotiating the withdrawal agreement.

“We want to find ways of providing the reassurance and clarification the British prime minister needs to be able to sell that deal in Westminster,” he said. “But that doesn’t involve reopening that withdrawal agreement and reopening that negotiation.”

A UK source said: “This is categorically not about isolating Ireland. We have a shared interest in getting a deal that reassures people’s concerns over the Irish border and meets our commitments to the Belfast agreement.

“These can only be made legally watertight if a deal is ratified by parliament and made law. There is a clear route to doing this, and we need to work together to make it happen.”

There are signs that Dublin is feeling pressure from Brussels to start planning for checks on goods going between Ireland and Northern Ireland in the event of a no-deal Brexit.

The taoiseach, Leo Varadkar, has insisted that he is not making any preparations for a hard border but privately he has been warned that Ireland will have to protect the EU’s border with the UK.

The commission issued fresh warnings on Monday to businesses over their need to adapt to new customs and indirect taxation systems such as VAT.

Pierre Moscovici, the commissioner for economic and financial affairs, taxation and customs, said: “With the risk of a no-deal Brexit increasing as we get closer to 29 March, the European commission and national customs authorities are working hard to be ready to introduce checks and controls on goods flowing between the EU and the UK. This is key to protecting our consumers and our internal market.”