Donald Trump, right, greets United Kingdom Independence Party leader Nigel Farage during a campaign rally at the Mississippi Coliseum on August 24, 2016 in Jackson, Mississippi.

One member of the group of Britons, who called themselves the "Bad Boys of Brexit," was Arron Banks, a wealthy businessman who donated millions to the campaign for Britain to leave the European Union.

That associate, Nigel Farage, was the leader of the UK Independence Party, or UKIP, and was one of the most prominent figures in the Brexit debate. The two people told the Post that Mueller's investigators have asked them about Farage's relationship to Trump associates during interviews as part of the ongoing probe into Russian meddling during the 2016 presidential election.

Special counsel Robert Mueller 's team is interested in a British businessman and his pro-Brexit associates' contacts with Russian diplomats and Trump campaign operatives, The Washington Post reported, citing two people who were asked by Mueller about one of those associates.

Banks provided dozens of emails and text messages to the newspaper reportedly showing a friendly rapport between him and the Russian ambassador to London, Alexander Yakovenko, in 2016.

All the while, the Post reported Thursday, Banks and a clique of other Brexiteers were angling to become more deeply involved in Donald Trump's presidential campaign.

Spokespersons for Farage and the special counsel's office did not immediately respond to CNBC's requests for comment. Banks could not be reached for comment.

The report shines more light on Russia's attempts to involve itself in major political events in the Western world as well as the willingness of key players in those events to respond favorably to Russian outreach.

In June 2016, for instance, ex-Trump campaign chairman Paul Manafort, along with Trump's son Donald Trump Jr. and his son-in-law, Jared Kushner, attended a meeting in Trump Tower with a Kremlin-connected lawyer whose intermediary had offered damaging information on Hillary Clinton.

After the stunning Brexit victory, in which Britain voted to leave the European Union, Banks reportedly met Yakovenko at the ambassador's residence. A few days later, Banks and his associates traveled to attend a fundraiser in Mississippi, where they had been invited by then-campaign chief executive Steve Bannon.

Banks and Farage both told the Post that they had not been contacted by Mueller's team. Trump's lawyer Rudy Giuliani told the newspaper that he had not heard anything about Yakovenko and that he had not been asked about it by Mueller. A spokesperson for Giuliani did not respond to CNBC's request for comment.

The simultaneous communications with Russian officials and Trump campaign members have also come to the attention of investigators in the United Kingdom, the Post reported.

Read the full report from The Washington Post.