Speaking after meeting the prime minister in Downing Street, the DUP leader said the idea, which is being mooted as a solution to the current impasse, was “undemocratic and unconstitutional”.
She claimed Mr Johnson had “confirmed his rejection” of a Northern Ireland-only backstop, despite reports that the government is considering the option, which was first proposed by the EU two years ago but rejected by Theresa May.
Any move to resurrect the proposal would be strongly opposed by the DUP, which is staunchly against any deal that could leave Northern Ireland and the rest of the UK operating under different rules.
Ms Foster said: “History teaches us that any deal relating to Northern Ireland which cannot command cross community support is doomed to failure. That is why the Northern Ireland backstop is flawed. Not one single unionist MLA in the Northern Ireland assembly supports it.
“The prime minister rejected a Northern Ireland only backstop in a letter to Donald Tusk on 19 August. It is undemocratic and unconstitutional and would place a tariff border between Northern Ireland and the rest of the United Kingdom. That would be unacceptable. “
She added: “During today’s meeting, the prime minister confirmed his rejection of the Northern Ireland only backstop and his commitment to securing a deal which works for the entire United Kingdom as well as our neighbours in the Republic of Ireland.”
Her comments came after Ireland’s EU commissioner, Phil Hogan, said ”the penny is finally dropping” in No10 on the need for the UK to compromise on the backstop.
Mr Hogan claimed that the EU had sensed a renewed willingness among UK ministers to consider a Northern Ireland-only solution.
He told The Irish Times: “Mr Johnson has made a proposal in the last few days talking about an all-Ireland food zone.
“That is certainly a clear indication of divergence between Northern Ireland and the Republic of Ireland, the EU and the rest of the UK. This is the first time that this has been spoken about by a British prime minister where they are prepared to accept some level of divergence between Northern Ireland and the rest of the UK.
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