British intelligence has blasted as “nonsense” an accusation leveled by White House spokesman Sean Spicer that former President Barack Obama used U.K. spies to wiretap Donald Trump during the presidential campaign.

At the White House press conference Thursday, Spicer referred to the theory, which had originally been presented on Fox News. In a TV appearance on “Fox & Friends,” Andrew Napolitano, a former judge and current Fox analyst, accused the Government Communications Headquarters — the U.K.’s version of the National Security Agency — of spying on Trump.

GCHQ blasted the claim in a rare public statement Thursday. “Recent allegations made by media commentator Judge Andrew Napolitano about GCHQ being asked to conduct ‘wire tapping’ against the then President Elect are nonsense,” said the statement provided to the British press and American journalists. “They are utterly ridiculous and should be ignored.”

In an emailed statement, Britain's GCHQ says such allegations are "nonsense. They are utterly ridiculous and should be ignored.” 3/3 — Jim Acosta (@Acosta) March 16, 2017

A British government source had told Reuters earlier in the week that the Fox story was “frankly, absurd.”

Spicer’s comments were surprising and risked antagonizing a key American ally. At the press conference, he quoted Napolitano as saying that “three intelligence sources have informed Fox News that President Obama went outside the chain of command. He didn’t use the NSA, he didn’t use the CIA, he didn’t use the FBI, and he didn’t use the Department of Justice; he used GCHQ.”

Obama was able to obtain Trump’s conversations through British intelligence and “there’s no American fingerprints on this,” said Spicer, adding: “Putting the published accounts and common sense together, this leads to a lot.”

.@Judgenap: Three intel sources have disclosed that Pres. Obama turned to British spies to get surveillance on Trump pic.twitter.com/IghCFm7qhO — FOX & friends (@foxandfriends) March 14, 2017

Spicer’s comments were particularly striking because they occurred shortly after the Senate intelligence committee issued a statement Thursday saying members could find no evidence that Obama had Trump Tower wiretapped. House intelligence committee chairman Devin Nunes (R-Calif.) also said on Wednesday that he had found no evidence to substantiate Trump’s claim.

British Member of Parliament Tim Farron blasted Spicer’s comments as “shameful.” Trump is “compromising the vital UK-US security relationship to try to cover his own embarrassment,” the Liberal Democrat leader told The Telegraph. “This harms our and U.S. security.”

A spokesman for Obama, as well as FBI director James Comey and former director of national intelligence James Clapper, have all denied that Obama had Trump wiretapped.

Trump initially accused Obama earlier this month in a series of tweets of having had him wiretapped during the presidential campaign.

Is it legal for a sitting President to be "wire tapping" a race for president prior to an election? Turned down by court earlier. A NEW LOW! — Donald J. Trump (@realDonaldTrump) March 4, 2017

I'd bet a good lawyer could make a great case out of the fact that President Obama was tapping my phones in October, just prior to Election! — Donald J. Trump (@realDonaldTrump) March 4, 2017

How low has President Obama gone to tapp my phones during the very sacred election process. This is Nixon/Watergate. Bad (or sick) guy! — Donald J. Trump (@realDonaldTrump) March 4, 2017

Trump appeared to admit earlier this week that he had based his claims on something he read. But he also vowed that some “very interesting items” will come to the “forefront over the next two weeks” concerning the issue, without offering any details.

Spicer now insists that “wiretapping” doesn’t actually mean wiretapping ― because the president put the word in quotes in his tweet — but rather any kind of surveillance. The White House has failed to offer any substantiation for that claim either.