Mrs May is to brief key ministers on negotiations with the European Union later.
The DUP is asking her to do something she...
He also stressed the EU's insistence that Britain must accept possible checks on goods moving between its mainland and its province of Northern Ireland, saying Brexit will trigger the need for customs, value-added tax and compliance checks with European Union standards.
Commenting on the Irish backstop, Barnier said the EU's plan to keep Northern Ireland in the Single Market and customs union would help keep the border invisible - a goal of both sets of negotiators.
The party's Brexit spokesman Sammy Wilson later explicitly warned the Government against doing a deal that kept Northern Ireland in the Single Market, writing in the Telegraph the party could not support "any deal which includes such economically and constitutionally damaging arrangements".
"If they haven't, there'll be consequences, and one of the consequences is the votes that we have promised to deliver for their domestic legislation will not be forthcoming".
"And we are still open - we are still open - to the idea of having a customs union with the UK".
Princess Eugenie's wedding cake will be red velvet and chocolate design
The group says Eugenie does not carry out royal duties and that weddings are personal, private occasions, not affairs of state. And preparations for Eugenie and fiance Jack Brooksbank's cake are now underway ahead of their nuptials on Friday 12 October.
Labour demands that Britain retain "the exact same" perks it now has within the EU's customs union and single market - something May's so-called Chequers plan does not meet and which the EU rules out since London made a decision to leave both.
The DUP has threatened to vote against the government's budget if it goes ahead with the plan.
Dutch prime minister Mark Rutte said on Wednesday evening he is "cautiously optimistic" that progress will be made next week on the negotiations for Britain to leave the EU.
THERESA May will chair a meeting of her War Cabinet of senior ministers today to try to agree an Irish backstop plan that would keep all of the United Kingdom in the European customs union until a full trade deal can be agreed with Brussels.
A meeting between the UK Government and devolved administration was meanwhile witness to "heated exchanges" over Brexit and migration policy.
He said Mr Barnier's demands included "that we would stay as part of the single market, our laws in NI would be made in Brussels, not London, that we would not be able to be part of future United Kingdom trade deals, that the ECJ would make decisions about the rules and regulations in Northern Ireland".
The Prime Minister was reported to have played down the prospects of a breakthrough at next week's EU summit in Brussels, billed as the "moment of truth" by European Council president Donald Tusk.