Mary Lou McDonald has said that Ireland must not become collateral damage amid the “Tory civil war over Brexit”.
The Sinn Fein president was speaking after meeting business leaders in Belfast, along with vice president Michelle O’Neill.
She made the warning on Monday afternoon as the Westminster Government of Theresa May appeared in turmoil following the resignations of Brexit Secretary David Davis and Foreign Secretary Boris Johnson.
“Our sole priority is the protection of Irish interests north and south,” Ms McDonald said.
“The civil war within the Tory Party is a matter for the Tories, and let no-one imagine that Ireland will be the collateral damage for the Tory Brexit or for that matter that we will pick up the tab for the Tory civil war.”
The Sinn Fein leader also warned that the UK should not “persist with a strategy that is about brinkmanship”.
“We need an answer to the Irish question, Europe has provided that answer by way of the Irish protocol,” she said.
“Mrs May seems still to be at sixes and sevens and is causing confusion in terms of what her and her Government’s position is.
“They say they are leaving the customs union and the single market, we know that the stated objectives of protecting the Good Friday Agreement, avoiding a hardening of the border, protecting citizens’ rights, demands that specific arrangements are agreed for the north of Ireland.”
Asked for her view on the Chequers deal, Ms McDonald claimed it appears to cherry-pick the internal market for the freedom of movement of goods.
“I don’t imagine that the European negotiators will countenance that,” she said.
“You can’t cherry-pick the internal market, and Europe can’t and won’t break its own rules.
“We await the publication of the white paper come Thursday.
“But all of this gets set to nothing if Mrs May insists the north of Ireland must exit the customs union and the single market.
“You can’t make that assertion on one hand, and on the other hand insist that you will ensure there is no hardening of the border and protect the Good Friday Agreement.
“That is a contradictory position.”
She added: “We didn’t choose Brexit, Brexit is a British phenomenon and Mrs May, or whoever the prime minister is, needs to keep their word and their stated position in protecting the Good Friday Agreement.”
Ms McDonald also insisted that her party is ready for a snap general election if it comes to that.
“We are always ready for elections, more so than any political party not only in Ireland but across these islands,” she said.
Meanwhile, Alliance Party Brexit spokesman Stephen Farry accused Mrs May of “passing up an opportunity to show leadership on Brexit”.
“This Government is now a complete shambles, with major resignations and the Prime Minister trying to sell a Brexit plan that is incoherent, bureaucratic and economically damaging, with no chance of it being accepted,” he said.
“With no viable plan and in chaos, the UK is ever closer to the cliff-edge of a no-deal outcome on Brexit, with all of the catastrophic economic and security implications.
“The stark reality is much of the Chequers plan and forthcoming white paper is about the future relationship.
“The immediate challenge is to sign up to the backstop. There can be no withdrawal agreement or transition deal around this.”