London: Britain said on Friday it had received White House assurances that claims it had snooped on Donald Trump would not be repeated, after spy agency GCHQ dismissed them as "utterly ridiculous" in a rare public denial.
Prime Minister Theresa May's spokesman reiterated GCHQ's denial of the claims -- which had been repeated by the US president's spokesman on Thursday -- as "utterly ridiculous" and said they "should be ignored".
"We have made this clear to the administration and have received assurances that these allegations will not be repeated," the spokesman said.
"The facts is, within the Five Eyes pact, we cannot use each other's capabilities to circumvent our laws," he said.
"We have a close, special relationship with the White House and that allows us to raise concerns as and when they arise as was true in this case."
Britain and the United States -- along with Australia, Canada and New Zealand -- are part of the "Five Eyes" intelligence-sharing alliance forged from the embers of World War II.
Late on Thursday, 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."
The press office of GCHQ, the Government Communications Headquarters, told AFP on Friday that it was "not unusual" for the agency to make public comment but acknowledged that "perhaps the tone of it was unusual".
The electronic eavesdropping agency does not normally comment on intelligence matters, though it has stepped up its public relations in recent months, including for recruitment drives and warnings on cyber-security.
'Harms our security'
Trump accused former US president Barack Obama on March 4 of a Nixon/Watergate-like wiretapping plot that would almost certainly break US law.
In the subsequent Fox report, Napolitano claimed that "three intelligence sources have informed Fox News that President Obama went outside the chain of command" to order the surveillance.
"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," Napolitano said, claiming that Obama used GCHQ to circumvent US law.
Trump's spokesman Sean Spicer repeated the allegations on Thursday, quoting from the Fox News report in which Napolitano spoke.
Members of Congress from both parties who are investigating the claims have found no evidence to support them.
Tim Farron, leader of Britain's opposition Liberal Democrats, called Spicer's repetition of the claims made by Napolitano "shameful".
"Trump is compromising the vital UK-US security relationship to try to cover his own embarrassment," he said, adding: "This harms our and US security."