Virtually all of the credibility of the so-called Steele dossier — and the Trump-Russia collusion narrative and investigations it spawned — hinges on Christopher Steele’s vaunted reputation as a former British intelligence agent who spied on Moscow and still maintains a network of sources inside the Kremlin.

But now we are finding out from newly released transcripts that he never even set foot inside Russia to compile his dossier, and that he relied instead on an ex-journalist-turned-p.r. consultant to do much of his investigating there. In fact, this non-intelligence figure may be his main “Russian source” of information.

Rep. Trey Gowdy (R-South Carolina) asked Steele’s Clinton-paid handler Glenn Simpson, during the House Intelligence Committee’s Nov. 14 closed-door hearing, if Steele had gone “to Russia as part of this project,” to which Simpson replied, “No, sir.” Steele, at the time he compiled the dossier, hadn’t been back to Russia in 17 years.

So, Gowdy pressed, “How was he able to accumulate information in Russia if he didn’t go?” Simpson claimed that Steele ran a “network of subsources or subcontractors” who traveled around Russia and gathered information for him.

But it turns out the primary subcontractor worked not for Steele but for Simpson at Washington-based Fusion GPS, and he contributed key material for the investigation of Trump underwritten by the Clinton campaign. His name is Edward Baumgartner, a British national who speaks fluent Russian and runs a p.r. shop out of London (and who spent 2016 tweeting his forceful opposition to Trump’s candidacy).

While Baumgartner was working on the dossier, he was also working for Simpson on another case to smear an anti-Putin whistleblower in an effort to help Putin-tied company Prevezon defend itself against US charges of money laundering.

During that contract, which ran through October 2016, Baumgartner worked closely in Moscow with the Russian lawyer who lobbied Donald Trump Jr. at a now-infamous Trump Tower meeting in June 2016 to help lift US sanctions on Russia. Her talking points were written by Simpson, who also dealt directly with the lawyer, Natalia Veselnitskaya.

During the case, Simpson and Baumgartner also met with her partner, former Russian military intelligence officer Rinat Akhmetshin.

As the Prevezon case was winding down, Simpson said he assigned Baumgartner, who shares his enmity toward Trump, to help dig up dirt on him. Baumgartner contributed research targeting the central Trump campaign figures charged in the dossier.

“I remember assigning him to do work in the summer or fall of 2016 on Michael Cohen’s business connections to Russia and Ukraine and his father-in-law’s background in Russia. And so he worked on both. And I think Edward might have also worked on some [Paul] Manafort stuff.”

Cohen was Trump’s lawyer and Manafort was his short-lived campaign chairman. Baumgartner also compiled information on Carter Page, a volunteer Trump adviser. The dossier accuses all three Trump associates of conspiring with Kremlin officials to hack the Clinton campaign and remove US sanctions on Russia.

In the dossier, Baumgartner is likely the unnamed “friend” or “close colleague” of the alleged Russian insider sources, who we’re led to believe “confided” in that “mutual friend” who we’re told, in turn, communicated directly to Steele the unproven rumors about Cohen, Manafort and Page.

Asked by intel panel staff if he verified Steele’s “sources in Russia” or corroborated their information, Simpson said he’s never been to Russia himself and couldn’t “evaluate the credibility of someone on the other side of the [Atlantic].” Nor could he confirm that Steele actually spoke directly with any of his Russian sources.

Simpson says he completely deferred to Steele’s expertise and did not question his findings because of his “sterling reputation.” Simpson has pumped this guy up to be the real-life 007 so deep inside the Kremlin, he didn’t have to corroborate his information, yet Steele was so far out of the hunt, his tradecraft so rusty, he apparently had to rely on a Russian translator who flacked for Putin to gather his so-called intelligence.

These latest revelations make it all the more baffling that the FBI took Steele so seriously. They also suggest the public should not make that mistake.

Paul Sperry is a former Hoover Institution media fellow and author of the bestseller “Infiltration.”