Varadkar mentions possibility of united Ireland
Slim hopes of a Brexit deal were vanishing after the DUP launched an extraordinary attack on Leo Varadkar, saying he would "go down in history as the Taoiseach who restored a hard Border".
In one of her party's most furious criticisms yet of the Irish Government, DUP leader Arlene Foster said Dublin had a "majoritarian desire to ride roughshod over unionism".
She also accused Tánaiste Simon Coveney of making "deeply unhelpful, obstructionist and intransigent" remarks.
She was responding to the Tánaiste's assertion that there were two "significant problems" with the alternative arrangements tabled by UK Prime Minister Boris Johnson.
He raised concerns that the plan includes customs checks on the island of Ireland and that the DUP would effectively be handed a veto on the situation every four years.
"We cannot support any proposal that suggests that one party or indeed a minority in Northern Ireland could make the decision for the majority in terms of how these proposals would be implemented in the future.
"That is not consistent with the Good Friday Agreement. It is not something we could possibly support as part of any final deal," Mr Coveney told the Dáil.
A similar message was delivered by the Taoiseach on trip to Scandinavia where he is shoring up solidarity among EU states.
At a press conference in Sweden, Mr Varadkar did theorise that a united Ireland would be one way of keeping an open Border on the island.
He told reporters there were now polls which suggested there was a majority for Irish reunification, as he offered it as one of five possible solutions to the Brexit crisis - and said it was one that would be acceptable to the Irish Government.
He said new UK plans for the Border "fall short in a number of aspects" and that the Irish Government would not "countenance" putting checks between north and south in any Brexit deal.
The Taoiseach said there were five ways to avoid a hard Border on the island:
1. A united Ireland;
2. The UK decides to stay in the EU;
3. The UK remains in the EU's single market and customs union;
4. The backstop;
5. Ireland rejoins the UK, which he said "is never going to happen".
The commentary drew the ire of the DUP, which has backed Mr Johnson's proposal that Northern Ireland could remain aligned with the rules of the EU single market but must leave the customs union with the rest of the UK.
Ms Foster said the offer was the final one and could not be amended further.
In London, Mr Johnson said his plans had been driven by the need to "protect" and "fortify" the Good Friday Agreement.
But opposition leader Jeremy Corbyn argued that no Labour MP could support the "reckless deal", which he said would jeopardise peace.
In his analysis the Taoiseach cast doubt on Mr Johnson's latest proposals to replace the backstop, saying he didn't "fully understand" the suggestion that the North and the Republic be in different customs unions and that this would "somehow avoid there being tariffs, checks and customs posts on trade between north and south".
He told reporters there was "contradiction" between Mr Johnson's assurances in the House of Commons yesterday that there would be no new customs infrastructure and the details of the UK's submission to the EU's Brexit negotiating team.
It is understood he reiterated these points in phone calls with EU Commission President Jean-Claude Juncker and European Council President Donald Tusk.