A thumping electronic beat provides the soundtrack to the video as Nigel Farage appears in front of a bank of screens.

At first glance, it could be yet another of the Reform UK leader’s “second jobs” – whether promoting gold as a pension fallback or recording Cameo videos. And in a sense, it is: Farage is promoting a £2m cryptocurrency purchase by a company in which he has £215,000 invested, Stack BTC.

“So we are about to place our bitcoin order,” says Farage with a smile, drawing on the communication skills honed as a politician and GB News anchor.

After pressing a button, he shrugs theatrically as a bugle marks the “purchase” before the clip cuts to him standing on a roof with Kwasi Kwarteng, the former Tory chancellor known for his disastrous 2022 mini budget in the government of Liz Truss.

The promotional video – filmed last week at the London offices of the online digital currency wallet Blockchain.com, and released on the morning the Reform UK leader held his latest weekly press conference – drew new attention to Farage’s relationship with Stack BTC. The crypto business is chaired by Kwarteng, who previously described the currency as a “total crapshoot”, but has since undergone something of a conversion.

The business proposition is an unusual one. It is a “bitcoin treasury company”, and describes its strategy as “becoming a listed investment vehicle with a primary focus on bitcoin”.

In simple terms, it exists to accumulate the digital currency. When the price of bitcoin rises, its share price would generally be expected to follow suit; when the price falls, so would the share price.

Investors, such as Farage, therefore make paper gains when bitcoin does well without buying the currency directly. And Kwarteng, Farage and any others with an interest in Stack are incentivised to see bitcoin do well, with much less reason to note any downsides.

Hours after Stack posted the video, the Liberal Democrats asked the Financial Conduct Authority (FCA) to investigate whether Farage’s promotion of cryptocurrencies amounted to attempted market abuse.

“No politician should be exploiting their platform to potentially enrich themselves or specific vested interests,” wrote the party’s deputy leader, Daisy Cooper, who pointed to Reform’s history of campaigning for policies that would expand the use of cryptocurrency.

Farage or his party have previously called for deregulation, and proposed a new “bitcoin reserve fund” and the forcing of HMRC to accept crypto as a payment for taxes. Cooper also highlighted the £9m donation Reform received last year from Christopher Harborne, an investor in the cryptocurrency firm Tether, making it the largest donation of its kind in UK history.

And it wasn’t just the usual centrist and left-leaning suspects raising concerns about Farage’s link with Stack.

Fraser Nelson, the former editor of the Spectator, last month described it as “a scandal hiding in plain sight”, adding that most politicians sell shares to avoid the appearance of conflict of interest. He also argued that if investors concluded that Farage was within reach of No 10, and believed his party would promote crypto, “the upside becomes self-fulfilling. The investment is not just a bet on bitcoin but on political power itself.”

Nelson confronted Kwarteng on Times Radio on Monday, claiming that Farage was buying shares to personally profit and that the company had given him a bonus deal that could pay millions. This has been rejected by Stack, which said Farage had invested on the same terms as every other shareholder.

To laughter, the former Tory MP insisted it was not guaranteed that he or Farage were going to make “a tonne of money”.

“It’s a $2tn market, the bitcoin market. The idea that Farage can influence it is ridiculous,” said the former MP, who added that he was sure the Reform leader would put his shares in a blind trust, sell them or recuse himself from decisions on crypto if he entered government.

Kwarteng said that buying shares instead of bitcoin directly meant Farage was being maximally transparent. Regarding the Reform leader’s motives, Kwarteng noted: “Everyone who buys shares intends to make some sort of money from them.”

Some may ask why Farage is prepared to countenance a brand promotion alongside a former politician associated with economic catastrophe. Whatever his reasons, he appears to be earning what he has described as “good money” that started to come his way after years in politics, having previously complained of being “skint”.

Indeed, his investment in Stack appears to have benefited from his own profile. After he took a 6.3% stake in March, the share price of what was a relatively small company quadrupled at one point; while the price has dropped, the shares are still worth almost double what Farage paid. He has since bought an additional £60,650 stake at a higher price. On paper, the total value of his stake appears to have increased by more than £200,000.

Listed on the UK “challenger” stock exchange Aquis, Stack is one of a number of bitcoin companies building up a portfolio and channelling surplus cash into the digital currency. It was co-founded by Paul Withers, the owner of Direct Bullion, which has already paid Farage £226,200 for his promotional work as a brand ambassador for the gold company.

At another level, there is a constituency of wealthy crypto enthusiasts seemingly rewarding Reform for its role as the foremost cheerleader in British politics for the currency.

As well as Harborne, there is Ben Delo, a British billionaire who last week said he had given £4m to Reform since the start of the year, before the government’s cap on donations to political parties by British citizens living abroad came into effect.

Farage has cultivated a relationship with the crypto community for some time, where many share the distinctive libertarian ethos of key Reform figures, such as Zia Yusuf and Richard Tice.

In the case of Stack, the company has not been shy about wading into the political mire. On X, it told the broadcaster and activist Narinder Kaur that she was “completely ignorant on the subject” after she described bitcoin as a pyramid scheme, and it congratulated the Reform activist Matthew Goodwin on sales of his new book, describing it as a “wonderful accomplishment”.

Farage attended various crypto conferences last year, although at times appeared less than sure-footed in front of a diverse young audience. At one, jokes about the chancellor, Rachel Reeves, (“Rachel from accounts”) and the Italian prime minister, Giorgia Meloni, which might have caused laughter at a Reform rally, fell flat.

Nevertheless, the raising of bitcoin’s profile by Farage has been welcomed by major figures including Andrew Webley, the founder and chief executive of the Smarter Web company, a much larger bitcoin treasury and digital services business than Stack BTC.

“I’m not a political person but it is clearly a good thing for the sector to have somebody that might end up as prime minister taking bitcoin seriously,” said Webley, whose company is listed on the London Stock Exchange.

“If I walk down a street in, say, London, people won’t recognise me. It’s a different matter with Nigel Farage. Whatever you think about him, he has got people talking about bitcoin. This is about normalising things, starting a conversation and educating people.”

“It has been the best performing asset in the world over the last 20 years so they should have some exposure to it, if not put every penny in it,” added Webley, who has invited Farage and other politicians to the “bitcoin treasuries unconference” his company is hosting in his home town of Bristol in May.

At the same time, it is not hard to find unease in the bitcoin community about the involvement of Britain’s most polarising frontline politician. “It is not entirely helpful in some ways,” said one.

A spokesperson for Farage has described the Stack event as a “photocall”, adding: “Mr Farage is embracing the 21st century. He bought the [£2m of] crypto on behalf of Stack and not personally.” They added that Farage would do “whatever is appropriate” with his Stack shares if he entered government.

As for donations, Reform’s website says it does not accept anonymous donations and any above £500 are checked. A spokesperson for Reform told the BBC that “all parties need donations to run campaigns” and “Labour taking money from the trade unions is just one example”.