The Attorney General is focusing on the theory, aired on far-right conspiracy sites, and raised by Trump and Giuliani, that Ukraine framed   Vladimir Putin   over the US election in a complex triple-cross operation by impersonating Russian hackers.

Trump and Barr have also been asking other foreign governments for help in investigating the   FBI ,   CIA   and Mueller investigators. The US president has called on the Australian prime minister   Scott Morrison   for assistance, while the Attorney General has been on similar missions to the UK and Italy.

And the information being requested has left allies astonished. One British official with knowledge of Barr’s wish-list presented to London commented that “it is like nothing we have come across before, they are basically asking, in quite robust terms, for help in doing a hatchet job on their own intelligence services.”

The UK, in particular, has been viewed by Trump followers, especially far-right conspiracy theorists, as a deep source of woes for the president.

The claims that Trump was the Muscovian candidate for the White House effectively began to take shape after a meeting in May 2016 between   Alexander Downer , the then Australian High Commissioner in London, and   George Papadopoulos , a foreign policy advisor for the Trump campaign, at a bar, the Kensington Wine Rooms in west London.

Downer passed on what he had heard to Australian officials, who shared it with the ASIO (Australian Security Intelligence Organisation), who in turn got in touch with the FBI. They then officially launched their investigation the following month.

Downer continues to live in London. He is the chair of trustees of the think-tank, Policy Exchange, and executive chairman of the International School of Government at King’s College, London, as well as holding positions in various businesses.

Then there is the dossier produced by   Christopher Steele , a former MI6 officer, on allegations that the Kremlin had compromising material, kompromat, on Trump. The report was passed on to FBI Director   James Comey , who was subsequently fired by Trump, in December 2017 by Senator   John McCain .

The Italian connection relates to Joseph Mifsud, a Maltese academic who had provided information to Papadopoulos about claims of Russian involvement.

Mifsud, who was affiliated to Link University in Rome, which has connections internationally with the security sector, has not been seen in public since November 2017. The Mueller report presented the academic as a possible Russian asset, but Trump supporters hold that he may have been working for Western intelligence services. The fact Steele’s first meeting with the FBI took place in Rome has reinforced the tale of dark machinations.

Two weeks ago Giuseppe Conte, the Italian prime minister, revealed that Barr had visited his country twice in the previous two months, alongside John Durham, the Connecticut attorney he had appointed to lead his investigation, and had pressed for information about the activities of the US intelligence services.

But it is Christopher Steele who is the particular bête-noire of Trump followers and they blame his report for starting the FBI investigation into Russian interference.

The House Intelligence Committee, then under Republican control, decided however that it was the Papadopoulous information which was the trigger. The same conclusion was separately drawn by the staff of the then Republican chair of the Committee,   Devin Nunes .

Trump loyalist Nunes, who his hometown newspaper in California has called “Trump’s stooge” had to step down at one stage over allegations that he was colluding with the White House during the House investigation. He had, in the past, tried to carry out his own ‘Barr-Lite’ version of investigating the investigators.

In August 2016, two staffers from the Nunes-run House Intelligence Committee suddenly turned up from the US at the London office of Steele’s company, Orbis. Not finding him there, they went to the office of his lawyer and demanded to see him.

The timing of the visit was of importance. Mueller and the Senate Intelligence Committee, carrying out separate Russia investigations, were making progress in their attempts to speak to the former MI6 officer. The two men had come with the aim, it was suspected, of intimidating Steele. Nothing discernible appears to have resulted from their trip.

Julian Assange   is another UK connection in the narrative. A year before Trump won the election Assange, holed up in the Ecuadorian embassy in London, had told his colleagues in WikiLeaks, the organisation he founded, in a Twitter group chat that Hillary Clinton was a “bright, well connected, sadistic sociopath” and it would be better if the Republicans could seize power. WikiLeaks subsequently disseminated emails stolen, as multiple investigations have established, from Democratic Party computers by Russian hackers. Assange is in prison in the UK facing extradition to the US for alleged espionage offences.

A number of Trump associates have been under investigation by Mueller for their links to Assange. These include Roger Stone, a long-term and close advisor to the US president who was arrested last January. He goes on trial next week on charges of lying to Congress, obstruction and witness tampering.

There have also been claims that Trump supporters not known to have been investigated by the Special Counsel had held clandestine meetings with Assange.

Glenn Simpson, whose Washington-based investigations firm hired Steele to compile the Trump report, told a US Congressional inquiry in January that   Nigel Farage   was a more frequent visitor to Assange than was known and that he had passed data on to Assange on “a thumb drive”.

Farage had long boasted of his closeness to Trump. On Thursday, speaking to Farage on his LBC show, the US president advised Boris Johnson to form an alliance with the Brexit Party leader to fight the coming UK general election.

The former Ukip leader visited Assange at the embassy in 2017 after returning from a trip to the US. The news of the visit broke after a member of the public saw him go into the building.

Farage had denied claims of any collusion, but refused to tell a number of news organisations what he had discussed with Assange. He said to me when I asked him about the matter: “I met Julian Assange just once. I went there in a journalistic capacity because like you I wanted to find out about the emails, no real answer was forthcoming. It is nonsense to say that I had met him secretly. Do you think one of the best known faces in the country can go into the embassy without people noticing?”

The Trump followers’ counter-narrative is that US intelligence and security services had deliberately, and wrongly, concluded that the Russians were behind the hacking. The real culprit, instead, they allege, was a private company,   Crowdstrike , which is run with an anti-Russian agenda.

Crowdstrike was a security firm hired by the Democratic Party to investigate the data breach and was the first of many, including western intelligence agencies, to find that Russia’s military intelligence agency, the GRU, had carried it out.

According to the conspiracy theories, Crowdstrike has a Ukrainian base, and its founder Dmitri Alperovitch is a Ukrainian who set up Putin in revenge for invading his homeland. But Alperovitch, in real life, is of Russian extraction and is a US citizen whose family came to America in the Soviet era. Crowdstrike is based not in Kiev, but California.

Every aspect of the Crowdstrike conspiracy tale has been disproved. But this has not stopped Trump from demanding that Zelensky looks into it, albeit in a somewhat incoherent manner, in the now infamous 25 July call to the Ukrainian president.

“I would like you to find out what happened with this whole situation with Ukraine, they say Crowdstrike. I guess you have one of your wealthy people. The server, they say Ukraine has it,” said the US president, according to notes of the conversation, released by the White House. In another part of the call Trump tells Zelensky “they say” Mueller “started with Ukraine”.

There is no evidence that the Special Counsel’s inquiry started with Ukraine. And we are yet to see where the Barr’s one will end. But the global reach the Attorney General has given the Trump counter-offensive ensures the repercussions, the accusations and recriminations, will be far and wide