LONDON — The former British intelligence officer who had a key role in drafting the dossier that alleged Russia holds compromising material and information on President-elect Donald Trump has gone into hiding, according to British reports.

Christopher Steele, a former MI6 officer and the director of a private-sector security firm in London, was named as the author of the 35-page packet making the explosive — and unsubstantiated — claims.

According to British media reports, Steele, 52, fled his home in Runfold, a village about 40 miles southwest of London on Wednesday morning before he was identified later in the day in a Wall Street Journal report.

The Post’s Rosalind S. Helderman explains the questions around the unconfirmed claims Russia has compromising information on Trump. (Bastien Inzaurralde/The Washington Post)

Before leaving his residence, Steele called his next-door neighbor Mike Hopper and asked if he could look after his three cats. Steele moved in about 18 months ago with his wife and four kids, his neighbor said.

“He has asked me to do that sort of thing before, so I didn’t take it as anything different. I was just about ready to go to work, and he called me and asked me to come in, gave me the key to the house. … He said that the family would be away for a while, would I mind looking after the animals?” Hopper said in an interview with The Washington Post.

Steele didn’t say where he was going or when he would be back, Hopper said.

The Guardian reported that Steele, a Cambridge University graduate, “was one of the more eminent Russia specialists for the Secret Intelligence Service,” better known as MI6, and had spent two years in Moscow in the 1990s. The newspaper said he was a contemporary and friend of Alex Younger, who now heads MI6, and at one point Steele was in charge of the service’s Russia desk.

Andrew Wood, a former British ambassador to Russia, told the BBC on Friday that Steele was a “very competent professional operator.”

“I do not think he would make things up. I don’t think he would necessarily always draw the correct judgment, but that’s not the same thing at all,” he added.

Wood also said he wasn’t surprised by reports that Steele has gone underground.

“Russia would certainly like to know where he got his information from — assuming his information is basically true and he hasn’t just made it up, which I don’t believe for a moment — and they’re accustomed to take action,” he said.

Director of National Intelligence James R. Clapper said Wednesday night that U.S. spy agencies “had not made any judgment that the information in this document is reliable.” But U.S. officials, speaking on the condition of anonymity to discuss intelligence matters, have said that Steele’s source network was viewed as credible.

A summary of the document was attached to a classified report on Russian interference in the presidential election that was given to President Obama and Trump. FBI Director James B. Comey pulled Trump aside at the briefing with intelligence chiefs in New York and told him about the attached summary, according to a U.S. official. CNN first reported the exchange.

The president-elect described the allegations as “all fake news — phony stuff” and said it was “a disgrace that that information would be let out.”

Steele’s London-based firm, Orbis Business Intelligence, was launched in 2009 by former British intelligence professionals, according to its website. The private intelligence outfit is located in an upscale area in London, not far from Buckingham Palace, and has a “global network of senior associates.”

“We provide strategic advice, mount intelligence-gathering operations and conduct complex, often cross-border investigations,” the firm says on its site.

Neither Steele nor his fellow director, Chris Burrows, could be reached for comment.

While Steele’s name was first published in the United States, the British media — not usually known for restraint — held off for several hours.

In Britain, there is a long-standing tacit agreement between the government and media whereby the media receives a notice — known officially as a “Defense and Security Media Advisory Notice” — and agrees not to publish certain information relating to national security. The system has been in place for decades and is purely voluntary.

The British media received such a notice Wednesday night, just after 6:30 p.m. local time.

“In view of media stories alleging that a former SIS officer was the source of the information which allegedly compromises President-elect Donald Trump would you and your journalists please seek my advice before making public that name,” wrote Air Vice-Marshal Andrew Vallance, secretary of the Defense and Security Media Advisory Committee, the body that issued the media notice.

“Irrespective of whether or not the stories are true, the public disclosure of that name would put the personal security of that individual directly at risk,” he wrote.

But after Steele’s name started appearing in the U.S. media, “it then became increasingly difficult to hold that line,” Vallance said in an interview.

He said his committee sent around another notice advising the British media to hold off until 10 p.m., thus allowing time for the former agent to “make arrangements for personal security."

Ellen Nakashima in Washington contributed to this report. 

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