Intelligence sources told The Telegraph that both Mr Spicer and General McMaster, the US National Security Adviser, have apologised over the claims. "The apology came direct from them," a source said. 

General 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.

Mr Spicer had earlier repeated claims that Barack Obama used GCHQ to spy on Mr Trump before he became president.

"He's able to get it and there's no American fingerprints on it," Mr Spicer said of the intelligence supposedly provided to Mr Obama by Britain.

"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."