UK Labour Party leader Sir Keir Starmer has accused Prime Minister Boris Johnson of taking a "wrecking ball" to relationships with Ireland and the EU with his controversial plan to unilaterally scrap aspects of the Northern Ireland Protocol.
Sir Keir is on a visit to Dublin to meet senior figures in the Irish government to discuss the deepening row over the post-Brexit trading arrangements.
On a visit to Trinity College in the city, Sir Keir was asked about comments from Taoiseach Micheal Martin this week when he warned that a UK Government move to legislate to override parts of the protocol would represent a "historic low point" in recent Anglo-Irish relations.
"As someone who cares deeply about the relationship between Ireland and the United Kingdom, I'm concerned about the comments that have been made," the Labour leader responded.
"Of course there are challenges with the protocol, but I think that we have faced much greater challenges than that in our shared history and I think that with flexibility on both sides, with good faith, statecraft, and trust around the negotiating table, we can deal with the remaining issues.
"My concern is that we have a Prime Minister who doesn't have those attributes. Trust is very important in all of this and this Prime Minister does not have the trust, or I fear he doesn't have the trust, to negotiate in the way that I actually think would lead to a solution to the problems.
"We've face bigger problems than this. With good faith, statecraft and trust around the negotiating table, which is what a Labour government would bring, these problems can be overcome.
But a Prime Minister without those attributes taking a wrecking ball to the relationship is not going to help anybody."
Meanwhile, Foreign Office minister James Cleverly has refused to directly say whether the First Treasury Counsel was consulted on plans to address issues arising from the Northern Ireland Protocol, citing a convention not to discuss legal advice given to Government.
Shadow Foreign Office minister Catherine West asked Mr Cleverly if the lawyer was directly consulted for his legal advice. She said "it would be unprecedented for the First Treasury Counsel not to be consulted on an issue of this importance".
"Can the minister confirm, yes or no, did the Government ask the First Treasury Counsel for a specific legal opinion on whether its plans around the protocol would breach international law? Yes or no?"
Mr Cleverly said: "The Government is confident that our plans abide to international law. The Government will be setting out its legal position in due course. And in accordance with the longstanding convention, we do not discuss legal advice given to Government."