Arlene Foster has urged the Prime Minister to reflect on her Brexit stance as she warned that the DUP will oppose her current proposals if they go to a parliamentary vote.
The DUP leader said “no unionist” could back Theresa May’s apparent advocacy of a withdrawal treaty that includes a Northern Ireland specific backstop measure to avoid a hard border on the island of Ireland.
In a letter to the DUP, which was leaked to the media, Mrs May insisted such a backstop would never come into force.
Mrs Foster said her party was fundamentally opposed to any divorce deal that saw Northern Ireland operate under a different regulatory arrangement to the rest of the UK.
Stormont’s former first minister insisted there were “many others” in the Conservative Party who could also not support the Prime Minister’s proposals.
“We would not be able to support this if it came to Parliament in the form that it is in the letter,” the DUP leader said.
“There are stages to go through before it comes to Parliament. She still has to have a cabinet meeting in relation to this matter and we believe there is a chance for her to reflect on the fact we will not be able to support it in its current form.”
In an interview with the BBC, Mrs Foster was asked did she trust the Prime Minister.
The DUP leader replied: “It’s not a question of trusting the Prime Minister, it is a question of what her proposals are for exiting the European Union.
“She has sent us where she believes she is currently at, and remember this is before she goes to Brussels to negotiate with them on what they believe is possible, but currently, as it stands, we could not support her proposals.”
Mrs Foster added: “Not only would we not be able to support what she has said to us but there are many others who would not be able to support it in her own party as well.”
She denied her party’s confidence and supply deal with the Tories was on “shaky ground”.
“I don’t think it leaves it on shaky ground because of course the confidence and supply agreement was entered into at a time of great national instability, we wanted to see stability in the Government at that time and we also wanted to deliver on a Brexit vote that had been taken.
“We don’t believe that the Prime Minister’s letter shows that we are delivering on that Brexit vote, so we will have to revisit all of that if this goes to a meaningful vote.”
She said the DUP would be asking for clarification of Mrs May’s intentions in further correspondence being sent to Downing Street on Friday night.