London (CNN) Until he was jailed for breaking the strict rules that govern the reporting of British court cases earlier this year, Tommy Robinson was among the most marginal of British political figures, little known outside the far-right circles in which he has moved for the past 10 years or so.

But when Donald Trump's former chief strategist Steve Bannon appeared on a radio show hosted by his populist fellow traveler Nigel Farage at the time of the US President's controversial visit to the UK earlier this month, he talked of Robinson as something of a cause célèbre.

"I don't think he's a bad guy. I think he's a solid guy and I think he's got to be released from prison," Bannon told Farage. In a furious off-air exchange after the show had ended, Bannon went further. "Tommy Robinson is the f***ing backbone of this country. You lose guys like Tommy Robinson, you're not going to have a country," he said, according to audio leaked to Buzzfeed.

It was a ringing endorsement from a leading figure in the US alt-right for someone who has so far largely failed to break out of fringe politics in the UK. Robinson, whose real name is Stephen Yaxley-Lennon, founded the English Defence League in 2009, a group that described itself as "the forefront of the counter-jihad." He left the EDL in 2013 but continued as a far-right activist, attacking the influence of Islamic extremism and arguing against Muslim immigration. He has been convicted of assault , and served jail terms for fraud and an attempt to enter the US on a false passport.

Bannon did not mention any of this on Farage's radio show. Instead, he concerned himself with Robinson's involvement in a trial of four Pakistani men accused of sexual offenses against white girls in northern England. In May, Robinson pleaded guilty to contempt of court for a Facebook Live webcast he conducted while the trial was taking place, in which he filmed defendants as they arrived in court and discussed the trial. His actions breached tight restrictions intended to prevent British trials being prejudiced, and he was jailed for 13 months.

US official raises Robinson case

But while Bannon may have been the most prominent US figure to take up Robinson's cause, he was not the first. CNN has confirmed that, in June, a US State Department official, Sam Brownback, raised Robinson's case in a meeting with the British ambassador in Washington, Kim Darroch. Brownback, a former Republican governor of Kansas, was at the embassy in his role as US ambassador at large for international religious freedom

British officials do not deny that a meeting about issues of religious freedom took place, and that Robinson's case was raised.

What was said at the meeting is a matter of some dispute. A Reuters report on July 13, quoting two sources in the pro-Robinson camp, suggested the Trump administration might publicly criticize Britain's handling of the case if Robinson was not treated more sympathetically.

An official at the British Embassy would only say: "The characterization of the details of the conversation is not accurate."

The US State Department also disputed how the meeting was described. "We refute as completely false the reports which wrongly assert that Ambassador Brownback urged the UK government to act on this issue or threatened repercussions in any way."

Brownback's office referred CNN to the State Department.

Sam Brownback, ambassador at large for international religious freedom, speaking in May 2018.

Neither side would say why Brownback, who was narrowly confirmed in January only on the tie-breaking vote of Vice President Mike Pence, had even raised the issue. Robinson is not an American citizen and, although he is appealing the length of his sentence, does not claim to have been wrongly imprisoned.

British officials seemed surprised that Brownback had heard about Robinson in the first place.

An ally of Robinson, Raheem Kassam, told CNN he had briefed Brownback about the case. Kassam, who was London editor for the right-wing news website Breitbart when Bannon was its executive chairman, said it was discussed only briefly at the embassy meeting. "Brownback just said to keep an eye on it because many people were upset about it," Kassam said.

Robinson case attracts US attention

By that time, Robinson's cause had already begun to gain traction in the US. After he was sentenced in May, Robinson's supporters began mobilizing a social-media campaign under the #FreeTommy banner, arguing that -- despite his guilty plea -- he was unfairly jailed and his freedom of speech curtailed. The campaign drew the backing of the son of the US President, Donald Trump Jr, who tweeted on May 27: "Reason #1776 for the original #brexit. Don't let America follow in these footsteps."

A few days later, a small pro-Robinson demonstration took place outside the British Embassy in Washington. On June 12, a Republican US congressman, Rep. Paul Gosar of Arizona, voiced his support in a statement from the floor of the House of Representatives, in which he said the British government appeared "fearful of the truth."

Soon, Robinson found himself supported by the Middle East Forum (MEF), a Philadelphia-based group that "protects Western values from Middle Eastern threats," according to its website. Its founder, Daniel Pipes, has claimed that Europe has "an advanced Islamist problem" and refers to the British capital as "Londonistan."

The MEF has petitioned the State Department and Congress on Robinson's behalf, its director, Gregg Roman, told CNN. He also revealed the group spent "a five-figure" sum to provide Robinson with legal support and organize rallies. According to recent tax records, MEF has an income of over $4 million a year.

One of these rallies took place in London on July 14, day three of Trump's controversial visit to Britain and the day after huge anti-Trump protests thronged the center of London.

Supporters of Tommy Robinson in Trafalgar Square in central London on July 14, 2018.

The MEF flew Gosar to London to address Robinson's supporters, Roman said. "Many of you may not know me," Gosar boomed from a black podium on Trafaglar Square. "I'm a United States congressman from Arizona, but I suggest we know each other very well indeed." A crowd waving English and American flags cheered. "Despite being two nations separated by an ocean, we are also two nations united by a common language," Gosar said. "For years now, we have lived with a full-frontal assault on free speech," he added. "That's why, when I first heard of the case of Tommy Robinson, I could not stay silent." Gosar went on to describe the "Free Tommy" campaign as "a precursor to a campaign for your own First Amendment."

Asked to comment, Gosar's office referred CNN to his statement from the floor of the House.

Anti-Islam tone

Another speaker at the rally was Gerard Batten, a successor to Farage as leader of the UK Independence Party, the insurgent political movement that helped precipitate the British vote to leave the European Union.

As leader of UKIP, Farage steered the party clear of figures like Robinson, keen to appeal to a broader electoral base. But Batten has adopted a more strident anti-Islam tone, and enthusiastically embraced Robinson's cause.

Speaking to pro-Robinson supporters gathered in Trafalgar Square, Batten characterized Robinson as "a political prisoner" and said that "history will judge him as being on the right side of a struggle between good and evil." He went on to describe Islam as "a Muhammad cult" that is "completely alien to everything our country stands for."

A US congressman and the leader of UKIP addressed the pro-Robinson rally in London.

Robinson's supporters, in the US and the UK, seem to want to paint him as a free-speech martyr who can lead the anti-Islam fight in the UK when he emerges from prison. There are signs that they are having some success: In prison, Robinson has enjoyed a level of media coverage that, had he been free, might have been difficult to attain.

For his part, Bannon appears to have a bigger prize in sight. His interest in Robinson reflects his larger ambition to mobilize alt-right parties across Europe -- in interviews, Bannon has revealed plans for a Europe-wide forum called The Movement, with the aim of uniting rightwing parties. CNN asked Bannon's spokesperson for an interview; instead, she provided a contact for Kassam, the former Breitbart London editor. "There are so many liberal NGOs, but there are very few NGOs with the nation-state as a primary goal," Kassam said, confirming Bannon's plans.

He rebuffed claims that Bannon wants to incite a populist revolt against the European Union. "It's not about blowing up the EU, it's about returning to nation-state sovereignty."

As right-wing politics gains momentum across Europe and US politicians venture across the Atlantic in their support, Europe's far-right believe they have a friend in the White House. In between the British and American flags at the "Free Tommy" rally on July 14 were signs saying, "Britain loves Trump."

Soon, Tommy Robinson will be out of jail. By that time, thanks in part to Bannon, Gosar and others on the American alt-right, his position as poster boy for the movement in the UK will be confirmed.