Jeremy Hunt has said relations with the EU will be “poisoned for many years to come” if Brussels fails to budge in the Brexit talks, as the cabinet ministers leading the negotiations put on hold tentative plans to return to the Belgian capital.

Geoffrey Cox, the attorney general, and the Brexit secretary, Stephen Barclay, had been expected to resume their haggling on the Irish backstop on Friday.

But after what Cox described as “robust” talks earlier in the week, during which Michel Barnier, the EU’s chief negotiator, rejected the latest British proposals, the two sides appeared to have reached stalemate.

The foreign secretary, speaking on BBC Radio 4’s Today programme, said future generations would judge Brussels badly should it fail to soften its position.

Hunt said: “This is a moment of change in our relationship between the UK and the EU and history will judge both sides very badly if we get this wrong.

“We want to remain the best of friends with the EU. That means getting this agreement through in a way that doesn’t inject poison in our relations for many years to come.

“That is what the UK has said we want to do, it is what most people in the UK want and feel very strongly about.

“But it does need the EU also to be flexible in these situations and understand that we now have a very, very clear ask. We know what it would take to get a deal through the House of Commons and it is for a significant change that will allow the attorney general to change his advice to the government and say that we couldn’t be trapped in the customs union for ever.”

“That is not an unreasonable thing to ask”, Hunt added. “And we have, I think, made some progress in the last few days. There is a a bit more to make. It is entirely possible to get there and frankly, I think future generations, if this ends in acrimony, people will say the EU got this wrong, and I really hope they don’t.”

British officials close to the Brexit negotiations fear the EU is misreading the politics in London by discounting any chance of victory in the Commons vote on Tuesday, when Theresa May is hoping to claw back from January’s historic 230-vote defeat.

UK negotiators have been seeking to convince their EU counterparts that next week is the best chance of having the deal ratified and that now is the time to make a concession, rather than after 29 March, once an extension has potentially been granted and parliament takes control of the UK’s objectives in the talks.

A Brussels visit by Cox and Barclay had not been confirmed for Friday. But if talks had progressed on the British ideas for winning over MPs to the Brexit deal, sources on both sides had suggested that the cabinet ministers would be in Brussels, ahead of a sign-off by the prime minister during a possible Sunday visit to the EU’s headquarters.

UK officials insisted the situation remained “fluid” and that both men were on standby, should there be a breakthrough.

May will later on Friday call for the EU to engage with the latest British ideas during a speech delivered in Grimsby in Lincolnshire, which voted strongly for Brexit. “Just as MPs will face a big choice next week, the EU has to make a choice too”, she is expected to say.

“It is in the European interest for the UK to leave with a deal. We are working with them but the decisions that the European Union makes over the next few days will have a big impact on the outcome of the vote.”

While Barclay and Cox have not been in Brussels since Wednesday morning, Downing Street’s chief Brexit adviser, Olly Robbins, has been in technical talks, trying to find a way through the logjam.

But with just a few days to go before a Commons vote, the British and EU teams have this week been talking at cross-purposes, sources in Brussels said.

The EU team, led by Barnier, is seeking to offer MPs reassurance that the shared customs territory that the Irish backstop envisages, and Northern Ireland staying in the single market, will only ever be a temporary arrangement if it should come to pass.

Their focus has been on turning a series of pledges made in a letter in January by Jean-Claude Juncker, the president of the European commission, and his European council counterpart, Donald Tusk, into legally binding commitments through a joint interpretative instrument, a legal add-on to the withdrawal agreement.

They include stating the EU’s “firm determination” to have an alternative to the backstop ready before the end of 2020, to avoid it coming into force.

Should the backstop be triggered, both sides would set the “objective of making this period as short as possible”. A road map to this end is being drafted.

But UK officials, while welcoming the offer, claimed it was not enough to allow Cox to revise his legal advice, given to MPs ahead of the last vote, that the backstop could be in force “indefinitely”.

Whitehall sources said Cox was not willing to change his opinion without a sufficiently significant move by the EU.

Cox is determined to get the possibility of legal redress should the EU try to “trap” Britain in the backstop.

His proposal has been for an arbitration panel, already foreseen in article 169 of the withdrawal agreement, to have an enhanced role.

The five-person panel – two nominated by each side, and an independent member – has the task of adjudicating if either side fears that the other is not making their “best endeavours” to replace the backstop with an alternative, such as a technological fix.

In such a case, should the arbitration panel agree that all that should be done is not being done, they would send back their opinion to a joint committee, a political body compromising members from both sides, to resolve.

The EU and UK agreed in the withdrawal agreement that exit from the backstop would have to be a political decision made by both sides.

Cox is seeking to spin that on its head, turning a political judgment into a legal one, and in effect outsourcing the issue.

The arbitration panel, under his proposal, would have the power to release the UK from enforcing the customs elements of the backstop, should the British government be able to show that it has made all reasonable efforts to negotiate an alternative.

Elements of the backstop would remain – the EU’s deputy chief negotiator, Sabine Weyand, has described what would be left as a “mini-backstop” – but the UK would be free to pursue the independent trade policy of which the Brexiters dream.