US formally apologizes to UK after White House accuses British spy agencies of snooping on Trump
Sean Spicer (CNN/screen grab)

The United States government has issued a formal apology to its closest ally after White House Press Secretary Sean Spicer suggested that one of its intelligence agencies had colluded with former President Barack Obama to spy on President Donald Trump.

The Telegraph reports that both Spicer and National Security Adviser H.R. McMaster "directly" apologized for Spicer's accusations against British spy agency GCHQ, which reacted with fury to the press secretary's suggestion that it had worked with the Obama administration to surveil a political rival.

Spicer's source for the claim against GCHQ was Fox News legal analyst Andrew Napolitano, who cited unnamed intelligence sources to claim Obama had bypassed his own intelligence agencies and went straight to the British to snoop on Trump.

"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," Spicer said.

Spicer's accusation drew a furious reaction from GCHQ.

"Recent allegations made by media commentator Judge Andrew Napolitano about GCHQ being asked to conduct 'wiretapping' against the then president elect are nonsense," an agency spokesman said in response. "They are utterly ridiculous and should be ignored."