Sinn Fein leader Mary Lou McDonald speaks during an interview with Reuters in her office at Government buildings, in Dublin, Ireland, May 18, 2022. (Reuters)

Britain will be breaking international law by passing legislation that will unilaterally change the protocol of North Ireland that rules trade post-Brexit, according to Mary Lou McDonald, the president of Ireland's Sinn Fein party.

McDonald said there were mechanisms to improve applying the protocol involving trade between Ireland and Belgium.

"There is a willingness here, there is a willingness to engage by the European Commission, but the British government has refused to engage," she told Sky News.

"It has not been constructive, it has sought a destructive path, and is now proposing to introduce legislation that will undoubtedly breach international law."

PM Johnson using N. Ireland against EU: Sinn Fein leader

UK Prime Minister is playing games with Ireland and using it as a pawn in the country's ongoing trade battle with the European Union following the Brexit deal, Sinn Fein leader Mary Lou McDonald said last month.

Johnson will visit Belfast on Monday for talks after the pro-UK unionist Democratic Unionist Party (DPU) blocked the election of a speaker in the Stormont assembly, the Northern Ireland Assembly, just a week after the Sinn Fein emerged victorious following a game-changing election.

The British PM's talks will take place with politicians in Northern Ireland, but McDonald accused the premier of being in "cahoots" with the pro-London party stopping an executive and assembly sitting.

The Stormont by-laws stipulate that a new administration only be formed without the largest unionist party taking part.

"He has connived with the DUP to use Ireland, the north of Ireland, to use unionism in Ireland as a pawn in a wider game that is being played out with the European Union," McDonald said in reference to Johnson.

She went on to call his tactic and approach "shameful" and "absolutely not acceptable."

"It is very clear that the Tory government in London is in cahoots with the DUP to stall and to hold back progress, to frustrate the will of the people as expressed in the election, and that, to anybody who calls themselves a democrat, is clearly unacceptable and clearly shameful. And that case will be made to Boris Johnson," she stressed.

Following the latest election, the DUP became Northern Ireland's second-largest party, losing the seat it had kept since the formation of Northern Ireland in 1921.

PM Johnson using N. Ireland against EU: Sinn Fein leader

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