Britain's government is still hopeful it can secure a Brexit breakthrough with the European Union this weekend ahead of a key parliamentary vote on Prime Minister Theresa May's deal next week, Foreign Minister Jeremy Hunt said on Thursday.

With only 22 days before Britain is due to leave the EU, May has yet to get her deal passed by Britain's deeply divided parliament, raising doubts and further uncertainty over Brexit, the country's biggest shift in policy in more than 40 years.

May is struggling to convince the EU to agree to changes to the so-called Irish backstop, an insurance policy to prevent a hard border between the UK province of Northern Ireland and EU-member Ireland if a future trading relationship falls short.

Talks this week led by Attorney General Geoffrey Cox failed to secure EU agreement, with officials in Brussels criticising the British side's proposals and telling May's top lawyer to rework them and come back on Friday.

One UK government source said with the EU showing no sign of moving in the talks, there was little hope anything could change over the next 48 hours, raising doubts over whether May can win support for her deal in next Tuesday's big vote. But Hunt said there was complete clarity on both sides as to what it will take to get an agreement through parliament and that he was hopeful for progress.

“Now there are very exhaustive discussions on both sides to try and find a way to achieve (a solution),” he told reporters after giving a speech in Scotland on cyber attacks. “Both sides want to find a way through this and we're hoping for that success to happen this weekend in time for the vote.”

A weekend breakthrough would give just enough time for May to bring her deal back to parliament before Tuesday's so-called meaningful vote, when she hopes to reverse a crushing defeat lawmakers dealt her in January.

Time is of the essence, with many businesses increasingly concerned over the risk of a disorderly Brexit which they say could wreck the world's fifth-largest economy. Real estate agent Countrywide cited Brexit uncertainty for its forecast for flat full-year earnings.

Hero or zero?

Cox was charged by May to pursue talks with the EU to secure changes necessary to make the divorce deal more palatable to parliament. But he returned to London empty-handed after EU officials rejected his proposal for an arbitration panel to resolve disputes over any departure from the backstop arrangement, diplomats said.

The backstop has become the focus for the impasse over Brexit, which Britain voted for in 2016 in a decision that has deeply divided both country and parliament.

“Leave” supporters fear the backstop is little more than a trap to keep Britain in the EU's sphere even after Brexit — an argument disputed in Brussels where officials say it can only ever be temporary if it is used, an unlikely scenario.

“We don't like the backstop: we don't want to have to implement it and if we have to we don't want to stay in the backstop. We all agree that it should be temporary and that it's a last resort solution,” French Europe minister Nathalie Loiseau told BBC Radio .

She said there were no precise proposals in the talks on the backstop, a charge Cox denied, saying the two sides were discussing “detailed, coherent, careful proposals” and a text.

If May loses next Tuesday's vote, Britain will most probably have to delay its departure from the EU, finance minister Philip Hammond said, playing down the risk of the country leaving without a deal.

“The government is very clear where the will of parliament is on this. Parliament will vote not to leave the European Union without a deal,” Hammond told BBC Radio . “I have a high degree of confidence about that.”