Boris Johnson has been warned his new Brexit proposals prove he "does not understand Northern Ireland".
North Down independent MP Lady Hermon accused the Prime Minister of "dancing to the tune" of the Government's DUP allies while forgetting the majority in Northern Ireland voted to remain in the EU.
She also warned people in Northern Ireland are "extremely concerned" about the risk of introducing two borders.
But there was better news for the PM as Eurosceptic Tories offered warm words in the Commons to the latest proposals sent to the EU.
Mr Johnson's offer would see Northern Ireland remain tied to EU single market rules for trade in goods while leaving the customs union with the rest of the UK.
Nationalists have expressed anger over a proposal requiring the suspended Assembly to approve the new arrangements, with a vote every four years.
Speaking in the Commons, Lady Hermon said: "The Prime Minister's proposals prove quite clearly that he does not understand Northern Ireland.
"While the Prime Minister is perfectly happy, it seems, to dance to the tune of his friends in the Democratic Unionist Party, he forgets or chooses to ignore the fact that the DUP does not represent the majority of people in Northern Ireland.
"The DUP campaigned for Leave, along with [Mr Johnson], but the majority of people in Northern Ireland voted Remain.
"The majority of people in Northern Ireland will be extremely concerned by the proposals that he has tabled yesterday, which introduce two borders in Northern Ireland."
She added people in Northern Ireland "certainly do not want" the UK to leave the EU without a deal, adding: "What people in Northern Ireland really want, all of them, is to continue to enjoy the peace and stability delivered by the Belfast Good Friday Agreement."
Anna Soubry, of the Independent Group for Change, earlier noted no DUP MPs were in the Commons for Mr Johnson's statement.
She said: "The DUP do not represent the people of Northern Ireland. And I observe they cannot even be bothered to turn up today."
Conservative Sir Bill Cash, chairman of the European Scrutiny Committee, said he was "welcoming" indications of progress in these negotiations. Tory former minister Mark Francois, deputy chairman of the pro-Brexit European Research Group, said: "May I commend the Prime Minister's emphasis on a future free trade as his desired end state which is what many of us have wanted all along."
Mr Francois said the only one of the indicative votes carried out by MPs to determine which form of Brexit was agreeable to the House was the so-called Brady amendment.
He added: "The essence of which was to expunge the backstop in favour of alternative arrangements which passed the House of Commons on January 29 by 16 votes. Does this give him hope that this could get through?"
Mr Johnson replied: "Yes, it does."
Labour leader Jeremy Corbyn (left) said no Labour MP could support the "reckless deal", which he said would jeopardise the Good Friday Agreement.
Mr Johnson's plans would see NI apply EU rules on goods but stay in a customs territory with the UK.
But Mr Johnson has insisted there would be no need for checks or infrastructure at the frontier.
Former Northern Ireland Secretary James Brokenshire said: "I commend my right honourable friend on his clear intent to make sure we leave with a deal on October 31.
"He has set out a detailed and considered proposal, and despite the protestations of the party opposite, I hope the EU will engage with them and be constructive."
Mr Brokenshire added: "What further steps will he take to get Stormont back up and running, and what assurance can he give to the people of Northern Ireland for the absolute need for political decision making in its absence?"
In response, Mr Johnson said: "Clearly what this deal would offer is the opportunity for the executive and assembly of Northern Ireland, the people of Northern Ireland, to have even more of a say in their own destiny.
"And in that sense it takes forwards and builds on the peace process, one of the great achievements of the last 30 years. So I think it is full of hope for the people of Northern Ireland, but it might give them an extra incentive to get Stormont up and running, and I can assure him we are working very hard to do just that."