Theresa May would be “extremely foolish” to publish any new plans for the Irish border backstop without first running them past the DUP, Sammy Wilson has warned.
The DUP MP also declared that any proposals by the government to create a regulatory border in the Irish Sea as a way to unlock the Brexit impasse would not be tolerated by his party.
Downing Street is understood to be working on new plans to end the stalemate between the UK and the EU over how to manage the Irish border post-Brexit.
According to recent reports, the prime minister is said to be ready to back down on her opposition to new regulatory checks on goods moving between Great Britain and NI.
But the her partners in government, the DUP, have repeatedly and emphatically stated that any move which puts trade barriers between NI and the rest of the UK is a red line for the party.
Mrs May is dependent on the votes of DUP MPs to prop up her minority government in the Commons.
In a shot across the PM’s bow, DUP Brexit spokesperson Mr Wilson said his party “is not bluffing” on this issue.
He told the News Letter: “If she is rolling back on her pledge that there will be no barriers between NI and GB, then the prime minister should be under no illusions; we will vote against her deal and it will go nowhere.
“She would be making a very wrong calculation if she thinks we are making empty threats. We are not messing around.
“With all that in mind, she would be mad to make concessions on the issue of a regulatory border in the Irish Sea.”
Mr Wilson said his party had received assurances from Downing Street that any new plans for the backstop “will not contain any proposals which create problems for NI’s relationship with the rest of the UK”.
But he advised that Mrs May would be “extremely foolish” if she chose not to share her new backstop vision with the DUP before it is made public.
The East Antrim MP said the government would likely want to avoid a repeat of the drama that unfolded last December, when Mrs May’s draft Brexit offer to the EU had to be abandoned at the 11th hour following objections from the DUP.
“If the government has any sense then we will have sight of these plans when they are ready,” he added.
“Rather than make themselves look foolish, the smart thing would be to share those plans with us, or at least the working of any agreement, so we can make sure that it does not damage Northern Ireland.”
Outlining in stark terms the choices open to the PM, Mr Wilson said: “She can either kowtow to Brussels or she can keep her promises to the House of Commons and the people of the UK. It is as simple as that.
“She must also remember that every time she concedes something to the EU, they will come back for more.
“Mrs May needs to toughen up her stance against the EU and get a bit of dignity back.”
In a frank address to EU leaders at Downing Street last month, a defiant Mrs May vowed she would not assent to Northern Ireland being “permanently separated economically from the rest of the UK by a border down the Irish Sea”.
Meanwhile, NI Secretary Karen Bradley told the Conservative Party conference the government would “never ever allow a border down the Irish Sea”.