On Friday he announced that he had declassified potentially millions of pages of intelligence documents related to surveillance activities on his campaign and Barr would have "full and complete authority" to examine them. "So what I've done is I've declassified everything," Trump told reporters at the White House before departing on a trip to Japan. "He can look and I hope he looks at the UK and I hope he looks at Australia and I hope he looks at Ukraine. "I hope he looks at everything, because there was a hoax that was perpetrated on our country." Trump is believed to be operating without precedent by giving an official who is not in charge of an intelligence agency the power to reveal its secrets.

US Special Counsel Bob Mueller's report on links between the Trump campaign and Russia, pointed to a 2016 meeting between then Trump campaign aide George Papadopoulos and Australian then high commissioner to the UK, Alexander Downer, in a London bar as prompting the FBI to open its Trump-Russia probe. The FBI probe led to Mueller being appointed as special counsel. Papadopoulos has repeatedly claimed Downer spied on him during the bar meeting, a claim which Downer has rejected. Former Australian High Commissioner to the UK Alexander Downer. Credit:AAP Downer has said that Papadopoulos told him at the bar Russia had damaging material on Trump's presidential rival Hillary Clinton.

The information was forwarded to Canberra and then passed on to US intelligence services and the FBI. Papadopoulos denies telling Downer anything about Russia obtaining damaging information on Clinton. In response to Trump's announcement Papadopoulos tweeted: "I have kept the heat on the UK and Australia for a while now. They will finally be exposed. None more than Clinton errand boy, Alexander Downer." He continued: "Fortunately, so many of these clowns that started to spy on me were from the UK/Australia/Italy. Those governments have absolutely no loyalty to the Obama administration/Comey/Brennan now. They are going to be the straw that breaks the camel’s back."

Trump described the Russia probe as "an attempted coup or an attempted takedown of the President of the United States". George Papadopoulos, former campaign adviser for Donald Trump, outside court last year. Credit:Bloomberg Trump also said he might ask outgoing British Prime Minister Theresa May about "potential Five Eyes spying" on his campaign. "I may very well talk to her about that, yeah," Trump said. "There's word and rumour that the FBI and others were involved, CIA were involved, with the UK, having to do with the Russian hoax," Trump said.

Jim Himes, a Democrat member of the House Intelligence Committee, said Trump was damaging alliances and potentially exposing confidential sources for his own political purposes. "What the UK and Australia and New Zealand see is because the President, in order to forward a political fantasy, may blow our sources and methods, put our people at risk," Himes told CNN. "This is a very dangerous thing for the United States." Papadopoulos was one of Mueller's first convictions, with the former aide pleading guilty to lying to the FBI. He was sentenced to 14 days' jail. Papadopoulos, Republican members of Congress and right-wing US media figures have been urging the President to declassify the documents.

"It's the greatest hoax, probably, in the history of our country and somebody has to get to the bottom of it," Trump said. "We'll see. "But for a long period of time, they've wanted me to declassify and I did." A spokesman for Prime Minister Scott Morrison declined to comment on Trump's move to investigate the Australian government's role, saying only that "Australia and the United States are the closest of allies". "The Government has not commented on these matters and doing so could prejudice any ongoing investigation," the spokesman said.