Britain will "undoubtedly" break international law by bringing forward legislation to unilaterally change the protocol that governs trade in Northern Ireland, the Sinn Féin president has said.
Mary Lou McDonald said Northern Ireland Secretary Brandon Lewis was “talking through his hat” when he claimed the legislation would be “lawful” and “correct”.
Britain has been threatening for months to rip up the Northern Ireland protocol, a trade deal for the region that was struck by British prime minister Boris Johnson's government in order to secure a Brexit divorce and a wider trade agreement between Brussels and London.
London says the implementation of the protocol has damaged trade within the United Kingdom and threatens political stability in Northern Ireland.
Unionists are vociferously opposed to the protocol, claiming it has undermined the region’s place in the UK. The DUP has blocked the formation of a new powersharing government at Stormont following last month’s Assembly election in protest at the protocol.
But the Sinn Féin president said there were mechanisms to improve the application of the protocol involving Dublin and Brussels.
"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."
The new legislation is designed to simplify the rules but has drawn sharp criticism in Brussels and Washington where it is seen by many as an inflammatory move that violates an international treaty.
Asked if the new legislation will be in breach of the law, Mr Lewis told Sky News’ Sophy Ridge on Sunday programme: “The legislation we’ll outline tomorrow is within the law.
“What we’re going to do is lawful and it is correct. We will be setting out our legal position on this. People will see that what we’re proposing resolves the key issues within the protocol that don’t work.”
Mr Lewis accused the EU of being “disingenuous” about offering flexibilities on the protocol.
He told the BBC’s Sunday Morning programme: “What they’ve been saying consistently across the media and have been reported as saying is that they’re offering flexibilities. Well, they’re not.
“What the EU are offering is some flexibility based on a fully-implemented protocol. That would be, actually, worse than the situation we’ve got today.”
He added: “So, I do think they’ve been disingenuous in suggesting they’re being flexible when in fact they’ve not shown the flexibility that’s required to resolve these issues for the people of Northern Ireland.”
Good Friday Agreement
The protocol enabled Britain to leave the EU's single market and customs union without controls being re-imposed on the border between the Republic and the North, vital to the 1998 Belfast/Good Friday Agreement.
By striking such a deal, it effectively agreed to a customs border between Northern Ireland and Britain.
The Times newspaper reported last week that the legislation had undergone "substantial drafting and redrafting" after Mr Johnson, badly weakened by a narrow victory in a confidence vote, came under pressure by his Brexit-backing lawmakers to toughen the terms.
However Mr Johnson will need to secure support from all wings of the party to get the legislation through parliament. Four in 10 of his lawmakers voted to ditch Mr Johnson in the confidence vote, and some have already expressed concern about the bill.