Asked if MPs will get a vote on any deal, the PM says Parliament will be able to “express its view”.
Rishi Sunak has sidestepped questions about what a deal with the European Union on post-Brexit trading agreements for Northern Ireland could look like.
During PMQs, Labour leader Sir Keir Starmer challenged Mr Sunak over whether Northern Ireland would still be subject to some EU laws.
Mr Sunak said “intensive discussions” with the EU were ongoing.
Asked if MPs would get a vote on any deal, Mr Sunak said Parliament would be able to “express its view”.
Legally, the government only has to offer MPs a vote on any changes in limited circumstances but it will face pressure to give backbenchers a say.
Labour has said it would back the government in a vote. However, the prime minister could still face a rebellion from Brexit-supporting Conservative MPs.
Many in the European Research Group of Tory backbenchers are opposed to the EU’s top court, the European Court of Justice (ECJ), having a future role in overseeing any agreement.
When Sir Keir pressed the prime minister over whether this would be the case, Mr Sunak said the Labour leader was talking about a deal that was still being finalised and “he hasn’t even seen”.
He accused Sir Keir of wanting to give the EU “a blank cheque and agree to anything they offer”.
“It’s not a strategy, that’s surrender,” he added.
Mr Sunak told MPs: “I am a Conservative, a Brexiter and a unionist, and any agreement that we reach needs to tick all three boxes.
“It needs to ensure sovereignty for Northern Ireland, it needs to safeguard Northern Ireland’s place in our union, and it needs to find practical solutions to the problems faced by people and businesses.”
Sir Keir said Mr Sunak was not being “honest” with Tory MPs and “pulling the wool over their eyes”.
The prime minister also refused to confirm whether, if a deal was secured, he would drop the Northern Ireland Protocol Bill.
The legislation, which is currently paused in Parliament, would give the government powers to unilaterally scrap parts of the treaty and has been a source of tension with the EU.
The protocol, which came into effect in 2021, aims to ensure free movement of goods across the Irish land border by conducting checks between Northern Ireland and Great Britain instead.
Unionist parties oppose the current rules and argue that placing an effective border across the Irish Sea undermines Northern Ireland’s place within the UK.
Negotiations to try and resolve issues with the treaty have been going on for more than a year, and there were suggestions a resolution could come this week.
However, progress appears to have stalled and the leader of Northern Ireland’s largest unionist party, the DUP, has said “there are still some very key issues that need to be resolved”.
The party is preventing a devolved government being formed in Northern Ireland in protest until its concerns have been addressed.
A majority of members of the Stormont assembly are in favour of the protocol in some form remaining in place.
Sinn Féin, the Alliance Party and the SDLP have said improvements to the protocol are needed to ease its implementation.
During PMQs, DUP leader Sir Jeffrey Donaldson said it was “unacceptable that EU laws are imposed on Northern Ireland with no democratic scrutiny or consent” and called for the legally binding treaty text to be rewritten.
Mr Sunak said he had heard the demands “loud and clear”, adding that “addressing the democratic deficit is an essential part of the negotiations”.
The BBC’s Jessica Parker says that Brussels has insisted that renegotiating the text is a no-go, arguing sufficient flexibilities can be found within the existing treaty.
The UK has previously called for rewriting of the agreement, but it seems more likely at this stage that a fresh legal text will “overlay” the deal.
That way, the EU can say it has stuck to its guns of “no renegotiation” but the UK can say that the new agreement has changed the primary treaty and the way it operates.
Crucially the prime minister refused to clearly answer two key questions: if his government was planning to drop its controversial Protocol Bill.
And would Parliament get a vote on a final protocol deal?
To that question, the prime minister said MPs would be able to “express a view”? But is that the same as getting a vote?
DUP leader Sir Jeffrey Donaldson demanded the legally binding text of the protocol needed to be rewritten to restore Northern Ireland’s place in the UK.
In response, the prime minister chose his words carefully.
He said dealing with the democratic deficit was key but avoided assuring the DUP that it would be dealt with through legislation.
The DUP will judge any protocol deal on what changes in law and not what is said in the Commons chamber.