The U.S. government has issued a formal apology to the United Kingdom after White House press secretary Sean Spicer cited a Fox News report to accuse a British intelligence service of spying on Trump Tower on behalf of then-President Barack Obama.

The British newspaper The Telegraph reports that U.S. National Security Advisor H.R. McMaster “contacted Sir Mark Lyall Grant, the Prime Minister's National Security adviser, to apologise for the comments. Mr Spicer conveyed his apology through Sir Kim Darroch, Britain's US ambassador.”

Over the past two weeks, Spicer has issued a series of increasingly frantic statements to support President Donald Trump’s baseless conspiracy theory that Obama wiretapped him during the 2016 presidential campaign. Yesterday, after the chairmen and ranking members of the House and Senate intelligence committees said that they have seen no evidence to support Trump’s claim, Spicer read aloud from a series of news articles that he falsely claimed supported Trump’s statement.

Amid this litany, Spicer cited Fox News senior judicial analyst Andrew Napolitano’s anonymously sourced March 13 statement that Obama had relied on the U.K. Government Communications Headquarters (GCHQ) to obtain transcripts of “conversations involving President-elect Trump” with “no American fingerprints on this.”

As I noted yesterday, in making the comments, Spicer imperiled our relations with our closest ally in order to buttress an obviously false Trump statement. Napolitano is a conspiracy theorist who has suggested the government may have been involved in the 9/11 terrorist attacks. His claim about British intelligence appears to have originated with a report on the state-sponsored Russian news network RT, and a British security official denied the claim, telling Reuters it was “totally untrue and quite frankly absurd.”

Spicer’s decision to make the same allegation from the White House podium drew a furious response from GCHQ, as The Telegraph reported:

In a break from its normal practice of refusing to comment on allegations about its activities, a spokesman for GCHQ said: “Recent allegations made by media commentator Judge Andrew Napolitano about GCHQ being asked to conduct 'wiretapping' against the then president elect are nonsense. They are utterly ridiculous and should be ignored.”

The increased scrutiny of Fox News in the U.K. comes at an inopportune time for the network’s parent company, 21st Century Fox, and its CEO, Rupert Murdoch. 21st Century Fox is currently trying to take full control of the United Kingdom satellite broadcasting company Sky, which oversees Sky News. Yesterday, the British culture secretary, Karen Bradley, referred the $14.3 billion bid to British media regulator Ofcom, in part over concerns about whether the company is “whether Fox is committed to the required editorial standards, such as accuracy and impartial news coverage,” according to The Guardian. ​

The White House’s open insult to the British government comes after conservatives spent years trumping up baseless claims that Obama was trying to undermine our relationship with the United Kingdom.

Right-wing media figures for years decried the return to the U.K. of a bust of Winston Churchill that President George W. Bush had kept in the Oval Office when Obama took office, citing the move as evidence that Obama hated the British and had grievously insulted our strongest ally. When Trump had the bust returned to the Oval Office following his inauguration, conservative media outlets swooned.

Less than two months later, the White House has had to apologize to the British government for baselessly accusing the country of spying on Trump.

UPDATE: There is now an apparent dispute within the Trump administration over whether the White House actually apologized to the British. “US officials... disputed whether the Trump administration had gone as far as an apology,” according to BuzzFeed. But earlier this morning, CNN's White House reporter said that White House sources had told him McMaster and Spicer had apologized.

UPDATE 2: Asked about Spicer’s comments by a German reporter at today’s joint press conference with German Chancellor Angela Merkel, Trump said that he and Merkel had “something in common” --suggesting the Obama administration had spied on them both. Trump added: “And just to finish your question, we said nothing. All we did was quote a certain very talented legal mind who was the one responsible for saying that on television. I didn't make an opinion on it. That was a statement made by a very talented lawyer on Fox. And so you shouldn't be talking to me, you should be talking to Fox.”

UPDATE 3: According to Fox News anchor Shep Smith, “Fox News cannot confirm judge Napolitano's commentary. Fox News knows of no evidence of any kind that the president of the United States was surveilled at any time in any way, full stop.”