Peaky Blinders has come under fire from viewers who claim the sound quality on the series was "dodgy" and that there was too much swearing.
They said their enjoyment of the BBC Two series about gangsters - which stars Cillian Murphy - was affected by muffled dialogue.
One viewer said on Points Of View: "I was very disappointed with quality of the sound, which sounded very muffled to both myself and my husband.
"This detracted from our enjoyment of the programme and also our understanding of the plot."
Another viewer complained about the swearing, saying: "Nearly every sentence contained the F word, and I found the repetitive overuse of such expletives utterly spoilt the programme."
One man also pointed out that it was historically inaccurate, as such words wouldn't have been used in normal conversation in the 1920s, when the series is set.
"Until the early '70s it was simply not done to swear in mixed company. So the language was not only tedious but unnecessary," he said.
Others tweeted about the problem.
It isn't the first time a BBC show has faced criticism about mumbling, as hundreds of people complained about the sound in Jamaica Inn and crime drama Quirke in 2014.
This year Happy Valley viewers also complained that the sound quality was "shocking".