The News Letter understands that the next 72 hours will be crucial in determining government thinking on negotiations between the UK and EU over the controversial psot-Brexit trade deal.
It understood that Cabinet ministers are pessimistic that the EU is going to compromise over the protocol and that the UK may now have to unilaterally change it.
Following a call with European Commission vice-president Maros Sefcovic, a Foreign Office spokesman said Ms Truss made clear that the UK’s “overriding priority” is to protect peace and stability in Northern Ireland.
She told Mr Sefcovic the protocol has become “the greatest obstacle” to forming a new Northern Ireland Executive.
The DUP will refuse later today to nominate a speaker to the Stormont Assembly which means no power-sharing administration with Sinn Fein is possible until Sir Jeffrey Donaldson believes the protocol is radically altered.
According to the Foreign Office readout of the Truss call, Mr Sefcovic insisted that there is “no room to expand the EU negotiating mandate”.
The spokesman said: “The foreign secretary noted this with regret and said the situation in Northern Ireland is a matter of internal peace and security for the United Kingdom, and if the EU would not show the requisite flexibility to help solve those issues, then, as a responsible government, we would have no choice but to act.”
Mr Sefcovic described the UK’s threat to suspend elements of the Brexit agreement as “simply not acceptable”.
Urging Britain to “uphold the rule of law and live up to international obligations”, the EU’s chief negotiator said London’s stance could damage Northern Ireland’s peace deal.
The News Letter also understands that the government has detected a more flexible approach to the protocol from the Irish government in recent days with Irish Foreign Minister Simon Coveney suggesting solutions to the Irish Sea Border including “green lanes” at customs in NI ports that would allow free passage of goods into the Province from GB and “red lanes” that are destined for the Irish Republic and must be checked.