Relations have never been as bad with UK government ministers, the Tánaiste has said.
Leo Varadkar said he believes the UK is “not being even handed” when it comes to the Northern Ireland Protocol.
MPs voted earlier this week to give the Northern Ireland Protocol Bill a second reading. The legislation is designed to override parts of the post-Brexit deal to allay concerns over its impact on the UK.
It comes after the DUP said it will not nominate ministers to allow a new Stormont Executive to be formed until the UK takes actions on its concerns around the protocol.
However, the move by the UK has been branded as illegal and a clear breach of international law.
Mr Varadkar said the UK’s bid to unilaterally change the protocol was a “strategic mistake”.
He told BBC Northern Ireland’s The View programme that the EU would “not be threatened” by the UK’s approach to the ongoing stand-off.
“The British government had given commitments in the past that it would be even handed in its approach to Northern Ireland,” he said.
“I don’t think that’s the case when it comes to this government, they’re siding with one of the three blocs of opinion that now exist in Northern Ireland.
“And I think that’s a strategic mistake for people who want to preserve the union – to continue to impose things that a clear majority of people don’t want means more people will turn away from the union.
“It’s a peculiar policy coming from a government that purports to want to defend the union.”
Mr Varadkar also said that in his political lifetime, he had “never seen relations as bad” with UK ministers.
“We have a British government that doesn’t want to work hand in glove with the Irish government, it’s not even handed, it’s a government that wants to continue to have rows with the EU even though they’ve left,” he said.
“I think trust needs to be restored, the best way they can do that is by de-escalating this.
“Even if you have difficulties trusting someone, you still have to try to come to an agreement. If we can’t with this government, then a future government.”
Mr Varadkar also claimed the people of Northern Ireland are not being listened to, referring to a letter against the bill signed by members of Sinn Féin, the SDLP and the Alliance Party.
“The thing that does bother me the most actually is that the people of Northern Ireland aren’t being listened to by their sovereign government in Westminster,” he said.
“A letter was written, 52 MLAs out of 90 signed it. It’s almost as if British ministers didn’t read it or didn’t care, and they set out very clearly that they did not want the protocol revoked, and they did not accept this argument that the protocol undermined the Good Friday Agreement.
“Fifty-two out of 90s MLAs, and the British Government treats the views of majority of the elected representatives of Northern Ireland as irrelevant, and that’s a fundamental problem.”