Russian intelligence created a false trail linking the double agent Sergei Skripal to the former MI6 officer behind the Trump dossier before carrying out the Salisbury nerve agent attack, the Telegraph has been told.

Well-placed sources now believe that the plot to kill Col Skripal may have included a ‘black ops’ attempt to sow doubt on the veracity of the explosive dossier that claims Donald Trump received Kremlin backing.

The year before the attempted assassination of Col Skripal, a mysterious post on LinkedIn suggested his MI6 handler, who is not being named, worked as a “senior analyst” at Orbis Business Intelligence, the firm that produced the Trump dossier.

Orbis was co-founded by Christopher Steele, the former head of MI6’s Russia desk, who authored the Trump dossier.

Mr Steele’s dossier included the central claim that the Kremlin had been “cultivating, supporting and assisting Trump for at least five years” and the allegation that Russia was in possession of a video showing Mr Trump engaged lewd sex acts with prostitutes in Moscow.

Christopher Steele, the former MI6 agent who set-up Orbis Business Intelligence credit: PA

But a number of sources have told The Telegraph that the LinkedIn profile is false - if it ever properly existed at all - and that Skripal’s MI6 handler never worked for Orbis.

It is now suspected that the LinkedIn profile was created by the GRU, the Russian military intelligence unit which tried to kill Col Skripal with novichok nerve agent.

One reason would be to connect MI6 to Skripal’s murder and at the same time flag the possibility that the British secret service was behind the Trump dossier.

A well-placed source said: “By creating this link, they are suggesting that MI6 are involved with the dossier or Skripal or both. It adds to the confusion and acts as a wedge between the White House and Downing Street. It is exactly the kind of operation the Russians would order to sow confusion.”

The appearance of the false LinkedIn profile more than a year before the attempted murder of Col Skripal also raises the prospect the plot was being planned for some time.

Mishkin and Chepiga aka Petrov and Boshirov credit: PA

An internet hyperlink to the LinkedIn page appeared in an obscure blog posting in January 2017 - more than a year before the Salisbury attack - but the actual LinkedIn page itself has never been visible.

At the time the LinkedIn reference was made public, Russia was angrily denying any involvement in the attempted murder of Col Skripal. But an investigation led by counter-terror police and the security services proved two senior GRU agents - Anatoliy Chepiga and Alexander Mishkin - had carried out the nerve agent attack.

How a LinkedIn account caused a conspiracy theory field day

Nobody can really be sure why the Kremlin ordered the assassination of Sergei Skripal. In March last year, two senior, decorated officers with the GRU, Russia’s military intelligence unit, flew with Vladimir Putin’s blessing to Britain to kill the colonel who had sold secrets to MI6.

They smeared military grade nerve agent on his front door handle in Salisbury and then fled the country on the next flight back to Moscow, causing a huge diplomatic crisis while claiming the life of Dawn Sturgess, an innocent Salisbury resident.

The most likely motive was revenge although others have suggested Col Skripal, who was sent to the UK in a spy swap in 2010, may have signed his own death warrant by ‘remaining in the game’ and continuing to offer up intelligence to Putin’s rivals.

Sergei and Yulia Skripal

But there was another possibility - one that is utterly ludicrous and now disproved - that was none the less championed by conspiracy theorists. Namely, that the death of Col Skripal was not ordered by the Kremlin at all - but carried out by British agents to silence the former Russian intelligence officer.

The reason was simple. Col Skripal - so the theory went - had helped provide information to Christopher Steele, a former senior MI6 officer, who authored an extraordinary dossier on Donald Trump, alleging that the soon-to-be president was effectively a puppet of Putin. The dossier claimed that the Kremlin had been “cultivating, supporting and assisting Trump for at least five years”.

It also made the extraordinary claim that Russia was in possession of a video depicting Trump performing obscene sex acts with prostitutes during a 2013 visit to Moscow. Moscow The video was being used as a potential means for blackmail.

The Ritz Carlton in Moscow where Donald Trump is alleged to have engaged in sex with prostitutes credit: Alamy

But where was the evidence linking Col Skripal to the Trump dossier? There were dots to join but if conspiracy theorists peered hard enough, they could find the clue they were looking for.

It came in the form of an internet hyperlink - no longer working - that suggested the MI6 agent who had recruited and handled Col Skripal had gone on to work in retirement for Orbis Business Intelligence, the company co-founded by Mr Steele

Nobody has ever reproduced the LinkedIn page itself. But on an obscure blog posted in January 2017 - more than a year before the Salisbury nerve agent attack - there was a one line reference to it. Clicking on the link itself didn’t work but there was the claim that Skripal’s handler “is a senior analyst at Orbis Business Intelligence”.

The post was written in January 2017 by an author giving his identity only as ‘Oui’ at a time when Mr Steele was being outed as the author of the Trump dossier. It is not clear how ‘Oui’ came across the LinkedIn profile - or even if it was planted on the blog.

Donald Trump at the White House on Saturday credit: UPI / Barcroft Media

Little attention was paid to the claim at the time but when 14 months later Col Skripal and his daughter Yulia were poisoned, the single line took on new meaning. Media outlets, including the Telegraph, spotted the connection and reported upon it. A Google search for the name of the handler and ‘Orbis Business Intelligence’ threw up the handler’s LinkedIn page as the first result. The link needless to say did not work, adding to the mystery that perhaps British intelligence had forced its removal.

Several sources have now confirmed to the Telegraph that Col Skripal’s handler never did any work for Orbis. He was known to Mr Steele from their time together at MI6; Mr Steele ran MI6’s Russia desk. But crucially neither the handler nor Col Skripal himself provided any information or help for the Trump dossier.

Intelligence sources increasingly believe the LinkedIn claim was falsely placed there by Russian intelligence - presumably the GRU, as part of a ‘black ops’ campaign of disinformation. The reason is unclear but could be, according to informed sources, to undermine Mr Steele’s claims in the dossier by suggesting it is an MI6 plot to get Trump but also to discredit Col Skripal in the year before his assassination.

One well-placed source said: “By creating this link, they [the Russians] are suggesting that MI6 are involved with the dossier or Skripal or both. It adds to the confusion and acts as a wedge between the White House and Downing Street. It is exactly the kind of operation the Russians would order to sow confusion.”

Craig Murray and a friend after his resignation as ambassador in Uzbekistan credit: Brian Smith

It also suggests they were already laying the groundwork for the assassination attempt on Skripal more than a year later. Flight records show one of the assassins - Alexander Mishkin, using the false name Alexander Petrov, flew to the UK at least twice before the Salisbury attack - once in late 2016 and again in March 2017.

Sources have pointed out that if Skripal’s MI6 handler - a senior officer in MI6 - had ever worked for Orbis, he would never have been described as a “senior analyst”. The source said: “That’s a title that is used by 20-somethings just starting out in this kind of work. The agent who recruited Sergei Skripal would never be described as a senior analyst because he is much more experienced than that.

“The chronology is really important because this LinkedIn reference appears a long time before the attempt on Skripal but at a time when Christopher Steele is under scrutiny over the dossier. It’s possible the Russians were already laying a trail on Skripal. They were putting a wedge between Washington and London.”

In the months before Theresa May categorically accused the GRU of carrying out the nerve agent attack in a Commons’ statement, there had been speculation - much of it from the Kremlin - that MI6 had killed Col Skripal.

There were a lot of takers for such a theory at least in the months before the assassins were finally unmasked as Anatoly Chepiga and Alexander Mishkin, two senior GRU men previously awarded Russia’s highest honour by Putin himself. They were identified following a lengthy investigation that included studying hours of CCTV in Salisbury, cross checking with flight manifests, and forensic evidence left at a hotel room where they stayed in London. Intelligence agencies discovered their true identities.

But by then the conspiracy theory had already been seized upon, fuelled by the LinkedIn claim that Skripal’s handler was working for Orbis.

Craig Murray, Britain’s former ambassador to Uzbekistan who quit in protest at the West’s support for the country’s brutal dictator, was one of those leading the charge.

In his own blog posting in April, our former man in Tashkent wrote: “We still have no idea of who attacked Sergei Skripal and why. But the fact that, right from the start, the government blocked the media from mentioning [the MI6 handler], and put out denials that this has anything to do with Christopher Steele and Orbis, including lying that [the handler] had never been connected to Orbis, convinces me that this is the most promising direction in which to look.”

Mr Murray went on: “It never seemed likely to me that the Russians had decided to assassinate an inactive spy who they let out of prison many years ago, over something that happened in Moscow over a decade ago.”

The Trump dossier, said Mr Murray, was a “much more probable” explanation. Back in April, Mr Murray wouldn’t rule out Russia but thought it more likely “that the idea was to silence Skripal to close the danger that he would reveal his part in the concoction of this fraud.”

Mr Murray had seized on the LinkedIn thread. “The only clue,” he admitted, “is a reference to it, that seems to have originated in a post on the internet in January 2017, more than a year before the attempted assassination of Colonel Skripal in Salisbury.

“Steele, MI6 and the elements of the CIA which are out to get Trump, all would have a powerful motive to have the Skripal loose end tied.”

Last night Mr Murray accepted he had never found evidence of the LinkedIn page but thought it unlikely Russians' would have planted the link more than a year before trying to kill Skripal.

He now accepted the two Russian men were involved but was uncertain they were GRU agents. Col Skripal, he believed, was still a likely source for the Mr Steele's Trump dossier.

Sources are adamant that Col Skripal had no input in the Trump dossier. The subsequent reports, they insist, were based on a LinkedIn post that not only doesn’t appear to exist - but was put there by the Russian intelligence unit who carried out the attack in the first place.