But Brexit-supporting businessman Roger Kendrick challenged the prime minister over her plans, which he said would restrict the ability to strike trade deals with countries outside the European Union, telling Mrs May: "Think again about the economics of the whole thing". This isn't what the DUP foresaw when it signed its Confidence and Supply Agreement with the Conservative Party-especially after it secured "commitments" from Theresa May in December 2017 that their red lines would not be breached.
More than 70 lawmakers, including several in May's governing Conservative Party, had supported the so-called amendment to the finance bill, to demand the government publish the analysis before a vote on the deal comes before parliament.
Sammy Wilson, the DUP's Brexit spokesperson, told the BBC that the deal means that "the government has not honored its side of the bargain, [and] we tonight tried to spell out some of the consequences of that".
She said: "We don't want to oust the Prime Minister".
In Northern Ireland, the Agreement has been welcomed by most of the Remain supporting parties.
For Labour, shadow cabinet office minister Jon Trickett said the DUP's withdrawal of support on a Budget measure raised questions as to how long the Government could carry on in the face of widespread opposition to her Brexit deal.
"The withdrawal agreement meets our key objectives in terms of the integrity of the United Kingdom which is so important to all of us in government especially the prime minister".
Divisions within the camp of Brexiteer MPs in her Conservative Party meant that the 48 letters required to trigger a no-confidence vote have so far failed to materialise.
The only person who knows for sure how many votes are in is Graham Brady, the chairman of the 1922 Committee of rank-and-file Tory MPs.
The Prime Minister has made it incredibly clear to MPs over the last month or so, and more publicly in recent days, that she will not give an inch on this.
Michael Gove - who last week turned down the job of Brexit Secretary following the resignation of Dominic Raab - Andrea Leadsom, Penny Mordaunt, Liam Fox and Chris Grayling were all reported to be unhappy with the terms over the Northern Ireland border.
Downing Street said the talks would focus on lending more detail to the future framework document, but warned that the deal would probably not be finalised tomorrow.
Theresa May is facing opposition in both directions over her Brexit deal.
It's a delicate issue for May, because some in her party worry the extension could be used to trap Britain in the EU's rules indefinitely.
This being said, with regards to Brexit and the democratic consent of the people of Northern Ireland, voters indicated that the majority wanted no part of Brexit, with the Remain side in the north taking 55.77% of the vote.
A number of MPs both from the leading Conservative Party and the opposition parties argue that British voters should go back to the polls to vote on the options of going ahead with the current deal, leaving the European Union with no deal, or even remaining in the EU.
He said that if die-hard Tory Brexiteers refuse to back the PM's plan then the "consensus" in Government that Brexit must be delivered could break down altogether.