Theresa May's Brexit plans have been sharply criticised by both EU leaders and members of her own Conservative party.
The British Prime Minister again presented her 'Chequers' proposals to European counterparts at a summit in Salzburg this week.
However, European Council President Donald Tusk insisted the proposals on the future relationship 'would not work'.
Taoiseach Leo Varadkar dismissed suggestions there had been progress on the Irish backstop to avoid a hard border.
Jacob Rees-Mogg - a prominent pro-Brexit MP from Mrs May's own party - said the current plan isn't viable, claiming it will keep the UK "tied into the failing European Union economic model".
He argued: "The EU was not going to accept it, and it's not leaving the European Union.
"It won't protect jobs - it will deny us the opportunity to create jobs."
French President Emmanuel Macron, meanwhile, argued: "We all agreed on this today, the proposals in their current state are not acceptable. The Chequers plan cannot be take it or leave it."
Mrs May, insisted that her cabinet-approved Brexit proposals were the "only serious credible" way to avoid a hard border.
She'll face a key test of the plans - and the level of internal opposition to them - when they're discussed at the Conservative party conference in the UK, which gets underway on September 30th.