Christopher Steele, the former MI6 spy who prepared the explosive Trump report, has been approached about testifying before the US Senate Intelligence Committee's investigation into the new President's alleged links with Russia, The Independent can reveal.
Mr Steele's friends say it is currently unlikely he would be willing to travel to the US. But it is understood Democrats - as well as some Republicans - in Congress are prepared to facilitate discreet initial meetings in the UK or on other neutral territory.
John McCain, the former Republican presidential candidate, and chairman of the Senate Armed Services Committee, sent an intermediary to London in November last year to collect Mr Steele's dossier, which was subsequently passed personally by the Senator to FBI director James Comey.
And Mr Steele had, while carrying out his Trump inquiry, himself liaised for regular periods with the bureau.
Mr Trump has personally attacked Mr Steele, declaring the report on the Kremlin connection by the former MI6 officer as a fabricated work, put together by a "failed spy".
In reality, Mr Steele was, and continues to be, held in high regard by British security and intelligence services as well as the American security officials who worked with him in the past.
It emerged this week that the FBI had, at one stage, proposed to pay him to continue his investigation into Mr Trump and his associates.
But that deal fell through and Mr Steele ultimately continued to work without pay because he was so worried by what he was discovering.
Mr Steele has not yet responded to requests to meet with Senate officials - described as informal at this stage - for testimony, which have come over the last fortnight. But friends say he may be willing to speak about his investigation to senators and US officials if certain security conditions are met.
The development comes amid fresh revelations of the Trump administration's interaction with the Russians. It has emerged that Jeff Sessions, the Attorney General, was in contact with Moscow's ambassador to the US during the election campaign.
Mr Trump's national security adviser, Lieutenant General Michael Flynn, was forced to resign after details of similar communications surfaced last month.
It has also emerged that in the last days of Barack Obama's presidency, officials were so worried that the incoming Trump administration would try to suppress or destroy incriminating material that they passed on information to the intelligence agencies and senior figures in Congress.
There is now similar concern that the Trump White House is trying to sabotage the Russia investigations. Democrats have asked for an inquiry into attempts by White House chief of staff, Reince Priebus, to get the FBI to dismiss media reports about members of Mr Trump's coterie contacting Russian officials.
The drive to contact Mr Steele and others, according to those familiar with the issue, is to try and ensure that as much information as possible is gathered by the Senate Intelligence Committee.
The committee is carrying out its own investigation, separate from one being conducted by the FBI, on the Russian links and attempts by the Kremlin to interfere in the American political process. There will, however, be mutual sharing of relevant material.
The Washington Post this week reported the plan by the FBI to pay Mr Steele, who was one of MI6's foremost Russia specialists, to continue his inquiries.
The Independent understands that the offer came after the discovery of a campaign of cyber hacking on state electoral systems in September, which led to a public charge against Moscow by the Obama administration.
Mr Steele became involved in the Trump investigation through the Washington-based firm Fusion GPS, which had been hired by Republican opponents of Mr Trump in September 2015.
In June 2016, Mr Steele joined up with the team. In July, Mr Trump won the Republican nomination and the Democrats became new employers of Mr Steele and Fusion GPS. With that contract due to come to an end with the election, the FBI stepped in with its offer of funding.
Mr Steele has been regularly supplying information to the FBI. In June last year, for instance, he produced a memo which went to the bureau stating that Mr Trump's campaign team had agreed to a Russian request to dilute attention on Moscow's intervention in Ukraine.
Four days later Mr Trump stated that he would recognise Moscow's annexation of Crimea: officials involved in his campaign having already asked the Republican party's election platform to remove a pledge for military assistance to the Ukrainian government against separatist rebels in the east of the country.
Mr Steele claimed the Trump campaign was taking this path because it was aware that the Russians were hacking Democratic Party emails. The same day that Mr Trump spoke about Crimea, he called on the Kremlin to hack Hillary Clinton's emails.
However, Mr Steele became increasingly frustrated that the FBI was failing to take action on the intelligence from others as well as him.
He came to believe there was a cover-up, that a cabal within the bureau blocked a thorough inquiry into Mr Trump, focusing instead on the investigation into Hillary Clinton's emails. The MI6 officer's passing of information to the FBI ceased in December last year.
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