The former British spy apparently at the centre of a dossier containing embarrassing allegations involving Donald Trump has been described by ex-colleagues as a "thorough" and "highly regarded" professional who would not simply "pass on gossip".
Ex-MI6 officer Christopher Steele has apparently gone into hiding after being identified as the author of the report claiming Moscow held incriminating material on the US president-elect which it could use to blackmail him.
Mr Steele - who runs the London-based Orbis Business Intelligence Service - is said to have originally compiled the report for political opponents of Mr Trump in Washington.
One former colleague, who used to work for the Foreign Office, sprang to Mr Steele's defence - dismissing any suggestions the dossier was "fake news".
The source, described in the Guardian as a long-term friend, said: "The idea his work is fake or a cowboy operation is false - completely untrue.
"Chris is an experienced and highly-regarded professional. He's not the sort of person who will simply pass on gossip.
"If he puts something in a report, he believes there's sufficient credibility in it for it to be worth considering.
"Chris is a very straight guy. He could not have survived in the job he was in if he had been prone to flights of fancy or doing things in an ill-considered way."
Former British ambassador to Russia Sir Andrew Wood said he spoke to Republican senator John McCain at an international security conference in November about the existence of material that could compromise the president-elect.
He told the Independent: "Yes I did meet Senator McCain and his aides at the conference.
"The issue of Donald Trump and Russia was very much in the news and it was natural to talk about it. We spoke about the kind of activities the Russians can be engaged in.
"We also spoke about how Mr Trump may find himself in a position where there could be an attempt to blackmail him with Kompromat (the Russian term for compromising material) and claims that there were audio and video tapes in existence."
Sir Andrew, who was ambassador to Moscow between 1995 and 2000, denied having seen the dossier at the time of the meeting and added Mr Steele was "very professional and thorough".
Earlier, Downing Street refused to be drawn on whether the Government had offered any assistance to Mr Steele, who was reported to be in fear for his life after being named in media reports.
Former MI6 officer Harry Ferguson told BBC Newsnight that Mr Steele was reliable.
"Chris was a strong, middle-ranking SIS (MI6) officer and I don't quite agree that this was a sub-par report," he said.
"It seems to me that Chris was careful, as to try and find as many sources as possible to back these stories up, but also to make it clear that these are stories, and that what this intelligence report has at the moment is that it lacks that killer evidence."