BrewDog, the craft beer company that prides itself on a “punk” ethos, has been accused of acting like “just another multinational corporate machine” after forcing a family-run pub to change its name or face legal action.

The fast-growing Scottish brewer, which has burnished its underdog credentials with vocal criticism of how major brewers operate, recently launched a vodka brand called Lone Wolf. But it threatened legal action against a pub in Birmingham that opened under the same name, prompting allegations of bullying and hypocrisy from within the pubs and brewing community.

The brother and sister team behind the pub, Joshua and Sallie McFadyen, said they chose the name in 2015, before BrewDog unveiled its spirits brand. But they say they were too scared of the brewer’s financial muscle to fight back, deciding instead to change the name of their pub to the Wolf and adjust the signage and web page at their own expense.

Sallie McFadyen told the Guardian: “We had an email one day from their solicitors – and that was the first we knew of it – saying they had a trademarked spirit coming out. All our money has gone into refurbishing this place and getting it open and we don’t have the same money as they have. We were told we might have to incur their legal costs so we were panic-stricken.”

She said she and her brother chose the name the Lone Wolf because they had both previously worked for major pub companies and had decided to go it alone. They were also inspired by Sally’s dog, which “looks like a wolf”, echoing Brewdog’s own name, which is based on co-founder James Watt’s dog.

But they have been left disappointed by BrewDog’s decision to pursue them with the threat of legal action.

“It’s devastating because it was quite personal why we called it Lone Wolf,” Sallie McFadyen said. “We’ve come round to it now but it is a bit hypocritical because they make a lot of public statements saying how much they support independence and they don’t like a big corporate attitude. It seems to go against what they stand for and it was done in such a harsh way.”

Brewers and beer-lovers denounced BrewDog on social media for threatening an independent pub with legal action over the Lone Wolf name:

@TheWolfBham @BrewDog you should be ashamed for bullying this superb independent business. Shame on you! — Ellie (@Ellie717774) March 4, 2017

@TheWolfBham this is a simple demonstration that @BrewDog are just another multinational corporate machine. Not independent 'punk' movement — Backyard Brewhouse (@backyardbeer) March 1, 2017

BrewDog has raised money through an “Equity for Punks” scheme that allows drinkers to invest in return for shares and benefits such as discounts in its bars.

But its credentials as a challenger brand were called into question by beer industry figures, including brewers such as Walsall-based microbrewery Backyard Brewhouse, which labelled the Scottish company “just another multinational corporate machine”.

BrewDog declined to comment.

The company’s protection of its trademark is particularly surprising given that its founders have previously scorned copyright complaints against them.

Have decided there'll be no more @brewdog now for me after its shitty corporate attitude towards an independent @TheWolfBham #whoneedspunk — Mr4Stringz (@mr4stringz) March 3, 2017

Last year the company disputed a trademarking claim from the estate of Elvis Presley, which took issue with Brewdog’s Elvis Juice beer. In a statement on the firm’s website, it said: “Here at BrewDog, we don’t take too kindly to petty pen pushers attempting to make a fast buck by discrediting our good name under the guise of copyright infringement.”

BrewDog was also told it might face legal action from Wolverhampton Wanderers football club over claims that the branding for Lone Wolf is similar to the club’s own wolf’s head logo.

Some drinkers vowed never to let a drop of BrewDog’s beer pass their lips again in protest at its actions:

Drinkers who want to find BrewDog’s range won’t be able to do so at the Wolf. “To be honest it’s got nothing to do with that [the legal threat],” said Sallie McFadyen. “We try to keep to small breweries.”

BrewDog recently told its Equity for Punks shareholders that it is in talks with a major new investor, amid speculation that it is preparing to float some of its shares on the stock market.