Sinn Féin has insisted the DUP will never be allowed to wield a Stormont veto on the post-Brexit arrangements for the Irish Border.
Deputy leader Michelle O'Neill said there were no circumstances in which it would be acceptable for her former partners in government to have the power to block the continuation of Northern Ireland-specific measures.
She was reacting to the British government's proposal to hand the Northern Ireland Assembly a vote on whether to implement an all-island regulatory system post-Brexit and also give the devolved legislature a say on whether it wants to continue the arrangement after an initial four-year period.
Stormont voting structures mean that a bloc of MLAs from either the nationalist and unionist community can veto certain decisions, even if a majority of members back them. "Boris Johnson has today again rehearsed this role for the Stormont Assembly, an assembly which currently does not sit, currently does not sit because of the position of the DUP and the Tories and because of Brexit," Ms O'Neill said.
"There can be no situation whatsoever when the DUP are going to be afforded a veto, a lock, a blocking mechanism of any form in which to thwart any progress that could potentially be made on Brexit between both the EU and the British government.
"It is just a nonsense, an illogical statement to make and to keep making it over and over again."