HuffPost UK understands Pelosi, the leading Democrat, had a terse exchange with members of Jacob Rees-Mogg’s European Research Group over their view of the Northern Ireland border.
“Don’t condescend to me or to us,” sources said she told leading ERG member Mark Francois.
The Tory MPs had told the American delegation the concerns about the border had been “concocted” by Remainers.
But Francois said there had been no condescension. “In fact, Speaker Pelosi kindly said, twice in fact, ‘you guys are the most consistent of anyone we have spoken to over here about this whole thing’,” he said.
He added of the meeting: “The debate was about the implications of the Withdrawal Agreement for a hard border for Northern Ireland.”
“Several of the congressional delegations made references to barbed wire and watchtowers, dating from visits prior to 1998.
“We were at pains to point out that absolutely no-one was contemplating anything like that, and that even [Irish prime minister] Varadkar had recently confirmed there was no need for any physical infrastructure at the border. That was the essence of the debate.”
Pelosi used her visit to the UK to warn there was “no chance whatsoever” of Congress agreeing to a US-UK trade deal if Brexit harmed the Good Friday Agreement.
She repeated the warning during a speech in Dublin on Tuesday following a meeting with Varadkar.
During her time in London, Pelosi met British politicians including Chancellor Philip Hammond and the de-facto deputy prime minister David Lidington.
She also spoke with Theresa May, who is on holiday in Wales, on the phone.
The Democrat, who is second in line to the presidency behind Vice President Mike Pence, also had “candid discussions” with Jeremy Corbyn about anti-Semitism, Islamophobia, Brexit, Northern Ireland and Nato.
Her meeting with the Labour leader came after she met with former Labour MPs who defected to form The Independent Group.