Brian O'Dwyer

Writing for BuzzFeed News, Brian O’Dwyer of New York law firm O’Dwyer & Bernstien said he and other Irish-Americans “watch with great concern as politicians in London consider policies that would upset the peaceful resolution reached by all sides two decades ago”.

He suggests that Irish-Americans could play a crucial political role “if a post-Brexit UK seeks a trade deal with the United States without keeping an open border between the two Irelands”.

Mr O’Dwyer explains: “Exiting the EU will necessitate a new trade deal with the United States, which must be approved by Congress — where incoming chairs of relevant committees include a number of Irish-Americans and others with large Irish-American constituencies.

“You can expect an energised Irish-American community will flex all of its political muscle to defeat any treaty that does not contain firm commitments to maintain the seamless flow of people and goods across the Irish frontier.”

Mr O’Dwyer, who advised the White House in the 1990s during the talks that produced the Good Friday Agreement, highlighted the role played by the US in brokering the historic peace deal.

The UK Parliament is set to vote tonight on a draft Withdrawal Agreement which includes the controversial “backstop”. The provision aims to avert a hard border in Ireland even if the UK and the EU fail to agree a trade deal after the end of the post-Brexit transition period.