The former British spy who allegedly compiled a 'dirty' dossier smearing Donald Trump has been revealed.

Ex-MI6 man Christopher Steele is reported to be the source of a salacious file alleging the Kremlin had compromising evidence about Mr Trump's sex life, that it planned to use to blackmail him.

Yesterday, Mr Trump called the dossier, alleged to have been handed to US Senator John McCain by a former British ambassador, 'fake' and 'phony' and Moscow has dismissed the claims as 'utter nonsense.'

Mr Steele, 52, is said to be an expert in intelligence analysis and counter-terrorism and sources say he once worked with murdered Russian spy Alexander Litvinenko.

He is now the director of a private security and investigations firm called Orbis Business Intelligence Ltd, run out of plush offices in Belgravia, central London.

The involvement of a former British intelligence officer and ambassador is embarrassing for the Government with Theresa May under pressure to reassure the President-elect that the UK had nothing to do with the 35-page briefing.

The former British spy who allegedly compiled a 'dirty' dossier smearing Donald Trump has been revealed as Christopher Steele

The British security services had originally tried to block UK news organisations from naming Mr Steele by issuing a D-notice, which prevents the revelation of certain information for security reasons.

Mr Steele has now fled his home in Surrey, in fear of a backlash from the Kremlin and sources say he is 'terrified for his safety'.

In recent weeks, the former spy declined requests for interviews through an intermediary, who said the subject was 'too hot', reports the Wall Street Journal.

It is believed that Mr Steele could have worked with Russian agent Litvinenko.

The former KGB man was poisoned with polonium in London in 2006, with an inquiry finding his murder was on the orders of the Russian state.

It is believed that Christopher Steele once worked with murdered Russian spy Alexander Litvinenko (pictured, in hospital)

A source told the Times: 'I think he [Mr Steele] was one of the people who was working with Litvinenko.'

There have been conflicting reports on Mr Steele, with one source telling the newspaper he was not 'hugely impressed' with his expertise, while another said he was 'deeply expert' on Russian affairs.

His Linkedin profile is vague about his career history.

However, a diplomatic service list shows that the ex-spy was posted to the U.K.'s Moscow embassy in 1990 with the title of 'Second Secretary', serving under ambassador Sir Rodric Braithwaite.

It is not known how long he was posted at the embassy for, but he is later listed to have served at the U.K.'s Foreign & Commonweath Office in 2003, and as 'First Secretary' at the Britain's Paris embassy in 1998.

Orbis was founded in 2009 and a statement on the company's website says: 'Ethical business practice is a fundamental value for the Orbis Business Intelligence team.

'Our documented procedures, developed in conjunction with external legal counsel, ensure compliance with relevant UK, US and EU legislation.'

The firm also says it has a 'global network' of experts and business leaders and is able to execute 'intelligence gathering operations' and 'complex, often cross-border investigations.'

The dossier row threatens to overshadow the Prime Minister's visit to Washington later this month, at a time when she is desperate to secure a post-Brexit free trade deal with his administration.

Rubbishing the dossier, Mr Trump has claimed 'sick people put that c**p together', even suggesting that US secret services had leaked it to damage his reputation before his inauguration.

Donald Trump has dismissed claims in a flimsy dossier of 'dirt' on him but claims ex-MI6 agent Mr Steele was behind it has piled pressure on Theresa May to reassure him Britain had nothing to do with it

Fury: This angry denial came in a post on the billionaire tycoon's Twitter feed shortly after the report was published by Buzzfeed

Pictured: The doorways pictured lead to the offices of Orbis Business Intelligence Ltd in Belgravia, central London

A Downing Street spokeswoman said yesterday the Government was 'not aware' of the allegation that a ambassador was involved in passing on the memos to a US senator.

Diplomatic mission: Boris Johnson has been trying to build bridges with Trump's team during a visit to Washington this week (pictured)

The spokeswoman said No 10 would not be commenting further on the controversy, which could undo work carried out by Boris Johnson to build bridges with Trump's team during a visit to Washington this week.

Mr Steele was reportedly hired by enemies of Donald Trump and was asked to do a 'general' trawl on the billionaire's links to Russia. He was described as 'reliable, meticulous and well-informed' by one source.

Russian sources allegedly told the operative that they had extensive material on the now President-elect - including a secret film of him in the suite where President Obama stayed in Moscow, watching prostitutes committing degrading sex acts, specifically 'golden showers [urination]', on the bed where the president once slept.

Critics have questioned the credibility of the intelligence dossier because it contains a number of key spelling mistakes.

It also has mistaken references to areas of Moscow an expert on the city would be expected to get right and its claims are not backed up with evidence.

Carl Bernstein, the Watergate reporter who contributed to the first story about the dossier, claimed yesterday that Senator McCain was handed it by a former British ambassador to Moscow later last year.

TIMELINE: THE TRUMP DOSSIER 2007: The Ritz-Carlton opens in Moscow in 2007 2009: Barack Obama and his family stay there when they travel to the city 2013: Donald Trump visits Moscow to judge the Miss Universe pageant June 2015: Trump officially announces he is entering the race to become Republican presidential nominee 2015-16: A Republican rival hires an investigative firm to uncover dirt on Trump. By the time work has begun, Trump has won the primary vote but now a Democrat wants the same service July 2016: A large amount of material has been gathered on Trump based on sources, which is believed to be of huge consequence, if true. The allegations are passed to the FBI September 2016: The FBI asks for more information but gets no reply October 28: FBI Director James Comey announces the bureau will be investigating Hillary Clinton over mishandling of confidential emails October 31: The document on Trump is leaked to David Corn, of the Mother Jones online political magazine Nobember 9: Trump is elected President Later in November: The documents are mentioned in an intelligence report on Russian interference given to Barack Obama and Trump November 18: John McCain discovers the contents of the document December 9: McCain hands the dossier directly to Comey January 11: CNN publishes the story on Trump, followed by an unredacted version by Buzzfeed Advertisement

The Guardian last night reported that McCain met a man, who they describe as a 'western diplomat', at a conference in Novia Scotia, who informed him of the existence of the dossier.

The Senator then dispatched an ex-US official to an unknown meeting place, where he met the diplomat after being told to look out for a man clutching a copy of the Financial Times.

The pair then drove to the 'western diplomat's' house and discussed the document. It was unclear whether the 'western diplomat' was the former Russian ambassador referred to by Bernstein.

The identity of the former British ambassador has not been disclosed. There have been nine since 1985.

Only one former British ambassador to Moscow remains in UK government service, Sir Tim Barrow, who went on to be Foreign Office political director and is now Britain's ambassador to the European Union. There is no suggestion he is the source.

Bernstein told CNN: 'It came from a former British MI6 agent who was hired from a political opposition research firm in Washington who was doing work about Donald Trump for both republican and democratic candidates opposed to Trump.

President-elect Donald Trump blasted 'phony stuff' contained in a dirt dossier against him that was released and blasted whoever leaked it – mentioning the intelligence agencies

'They were looking at Trump's business ties, they saw some questionable things about Russians, about his businesses in Russia, they in turn hired this MI6 former investigator, he then came up with additional information from his Russian sources.

'He was very concerned by the implications of it, he then took it to an FBI colleague that he had known in his undercover work for years, he took it to this FBI man in Rome who turned it over to the bureau in Washington in August.

'And then, a former British ambassador to Russia independently was made aware of these findings and he took the information to John McCain – Senator John McCain of Arizona – in the period just after the election, and showed it to McCain – additional findings.

KREMLIN WRITES OFF MEMO AS 'NONSENSE' Russia has denied allegations that the Kremlin collected compromising information about U.S. President-elect Donald Trump. Dmitry Peskov, the spokesman for President Vladimir Putin, dismissed news reports as a 'complete fabrication and utter nonsense.' He insisted that the Kremlin 'does not engage in collecting compromising material'. He added: 'There are those who pump up such a tantrum and do their best to maintain a 'witch hunt', and by the way this is how president-elect Trump characterised this fake. 'And why is the continuation of this hysterical state needed? To force our relationship to stay degraded. 'It is a complete fake - not worth the paper it was written on.' The memo also states that Peskov 'controlled' another dossier containing compromising material on Hillary Clinton compiled over 'many years'. But Peskov denied there was any such material. 'This was absolutely fabricated, this is total nonsense. This is what is called 'pulp fiction'.' Advertisement

'McCain was sufficiently disturbed by what he read to take it to FBI director James Comey himself personally, they had a five minute meeting the two men, very little was said, McCain turned it over to him and is now awaiting what the FBI's response is to that information.'

Yesterday Donald Trump furiously denied he was ever briefed on a dossier of claims passed to intelligence chiefs that he was secretly taped watching degrading sex acts by prostitutes in Moscow.

He said he was never shown or told about the claims - published in full by Buzzfeed after a report by CNN - when he met intelligence chiefs last week.

'Does anyone believe that story? I'm also very much of a germophobe by the way,' he said at a press conference in New York.

He stared down the assembled media for the first time since he won the election Wednesday and opened with a blistering attack on the press and the intelligence community after the release of an unproven dirt dossier on him.

'It's all fake news. It's phony stuff. It didn't happen. And it was gotten by opponents of ours,' Trump said.

'Sick people – and they put that c**p together.'

Speaking on his LBC radio show tonight, former Ukip leader and Trump ally Nigel Farage claimed a member of the President-elect's team told him the allegations would just make more people think the 'establishment' were 'out to get Trump'.

Mr Farage added: 'I think he looks very much in control. I think support for him across America is growing.'

British MPs told MailOnline that Mrs May must act swiftly to reassure the President-elect that the report was not UK-sponsored.

No10 and the Foreign Office have flatly refused to comment on the memos - which were apparently commissioned by political opponents and have been furiously denied by Mr Trump.

Tory MP Philip Davies said Mrs May's planned visit to Washington in the coming weeks was a huge opportunity to revive the Special Relationship, and nothing should be allowed to overshadow it.

'I hope the British Government confirm to President-Elect Trump that the actions of this individual do not reflect the UK as a whole or the UK Government,' Mr Davies said.

'We look forward to the Trump presidency re-establishing the special relationship between the UK and the US.'

The extraordinary - and entirely unverified - allegations that Donald Trump ordered prostitutes to commit degrading sex acts in the Ritz-Carlton in Moscow are contained in the dossier

Part of the document, allegedly compiled by former British intelligence agent Mr Steele, is seen above. Click here to see the full document first published by Buzzfeed

Tory MP Andrew Bridgen said the timing of the allegations pointed towards an effort to smear Mr Trump just nine days before he takes over in the Oval Office.

He told MailOnline: 'The question is why has this story come out now? Everything happens for a reason. Most things happen for a reason.

'It already appears to be unravelling. Someone's released the story… I'm sure the source will be revealed in time.'

Conservative backbencher Nigel Evans told MailOnline: 'It looks like this originated at a time when somebody was trying to undermine his bid for the presidency.

'There was enough stuff that did come out, enough revelations about things that he said – some of which probably did damage his candidacy – that I would thought if there was anything there (in this dossier) it would have emerged.

'Trump is denying it. Putin is denying it. It seems to be one of these fake news things.'

Fellow MP Michael Fabricant said: 'I can well understand the President-Elect's concerns over these stories as they seek to delegitimise his election to President. There are some in the United States who would like to see a re-run of their General Election as part of an anti-Trump campaign.

The Russian embassy in London said the government was 'panicking' and trying to drive a wedge between US President-elect Donald Trump and Vladimir Putin

'They are like some of those in the UK who seek to over-turn the Referendum result and keep us in the European Union.'

Meanwhile, former Foreign Secretary Sir Malcolm Rifkind has said any Russian efforts to compromise Mr Trump would show they know he will be his 'own man'.

Sir Malcolm said Moscow's intelligence services see gathering compromising material against politicians as 'what they are paid for'.

The Tory grandee, who also served as chair of the powerful Intelligence and Security Committee, said he had no idea whether the dossier was real.

'The Russians are not assuming that Trump is going to be a friend,' he told MailOnline.

He said that gathering 'dirt' on foreign politicians was a key role for the Russian agencies.

'I have not the slightest doubt that the Russian intelligence agencies assume that is what they are paid for,' Sir Malcolm said.

'They have an interest, a role in finding out as much as they can about the personal lives of politicians.'

Sir Malcolm said he was not too concerned about the tensions between the incoming US administration and the intelligence agencies.

'I would have thought that the intelligence agencies, when they met Trump, would have made clear that their function is to share the information they have with whoever is the President.'

Mr Trump - who is due to be formally installed as president in nine days - has already dismissed the claims, tweeting: 'FAKE NEWS - A TOTAL POLITICAL WITCH HUNT!'

American intelligence agencies have also accused Russia of directly interfering in the presidential election by hacking the Democrat computer network and leaking damaging material about Hillary Clinton.

Foreign Secretary Boris Johnson yesterday that Russia was 'up to all sorts of very dirty tricks'.

Some 35 pages of memos drawn up by the former MI6 agent - said to have served in Russia in the 1990s - was published by Buzzfeed, which pointed out that it contained errors.