While British Prime Minister Theresa May insists she will follow the results of last year's Brexit referendum, her disastrous showing in elections last week has raised fresh questions about how - and if - Britain will leave the bloc.
Scotland's first minister Nicola Sturgeon on Thursday condemned what she called a "grubby deal" with the DUP, warning that it could undermine the peace process.
In calling a general election three years early, May had hoped to boost her slim majority ahead of Brexit talks starting later this month.
"I think it's very self-interested, putting party before peace in Northern Ireland - party interest before peace and stability in Northern Ireland - and I do think it's that serious".
The prospect of such a deal has already raised alarm in Dublin, where Prime Minister Enda Kenny has warned of the impact on peace in the British province, while the DUP's ultra-conservative views have also prompted criticism. Their worry is that it may make the negotiations a little skewed as it may feel like the British government is backing the DUP in talks rather than being objective.
Labour's James Dornan asked the First Minister if she shares his concern about the message a deal between the Conservatives and the DUP, who have used their veto to block legalising same-sex marriage in Northern Ireland five times, sends to the LGBTI community.
Foster's rivals in Northern Ireland, such as Sinn Fein's Gerry Adams, have objected.
"People knew that we were abstentionist MPs, they have elected us to represent them but not to take our seats".
The Conservatives have reached a "broad agreement" with the DUP, a source told AFP on Thursday. Why the secrecy as the world's media would have seen them arrive at Downing Street so why didn't they leave the way they had come? Until she does, she and her ministers are on borrowed time.
The Brexit negotiator asked London not to "waste time" and explained that it will take "several months to draw out the conditions of an orderly withdrawal, with hard and sensitive points of discussion".