LONDON — US President-elect Donald Trump on Friday declared the author of the bombshell dossier on his potential ties to Russia a "failed spy" on Friday. Christopher Steele's former colleagues and friends beg to differ.

In fact, there has been an avalanche of support for Steele's credentials in the British press over the past two days, the cumulative effect of which has been to add credibility to the unproven allegations against the US president-elect.

Here are some key things we now know about Steele:

It hasn't all been one-way traffic, however. The dossier, which BuzzFeed published in full on Tuesday, does have its detractors. Elements of it have been proved untrue, most notably its incorrect spelling of Russian conglomerate Alfa Group as "Alpha-Group." It also said Trump's personal lawyer, Michael Cohen, travelled to Prague to meet with Russian officials. Cohen has since said he has never been to Prague.

Then there was this from another former British ambassador to Moscow, Sir Tony Brenton. He told Sky News:

"I've seen quite a lot of intelligence on Russia, and there are some things in it which look pretty shaky. For example it claims that the Russians began to cultivate Donald Trump five years ago. If they did that they showed remarkable prescience because at the time he had nothing to do with American politics."

(Brenton is wrong on that last point: Trump publicly flirted with running for president in 2000, 2004 and 2012, even though he did not launch a full-blown campaign.)

Trump's view is clear: The dossier is dodgy, he has said stridently. But it may be a gamble.

"It's the biggest political bet he is ever going to make," Republican strategist Rick Wilson told the BBC. "The bet is this: He can bluster his way through this, there's nothing there. That at no point at any time in his multiple trips to Russia did he engage in any behaviour that was caught on tape. That's a big bet. If he's right, he's right. If he's not, it's going to have some significant consequences for his credibility."