BBC hit gangster drama Peaky Blinders has been accused of glorifying violence and promoting toxic masculinity by a US-based academic.

The award-winning show, which revolves around the lives of the fictional Shelby crime family in post-World War One Birmingham, has become one of the broadcaster's most popular programmes with an average four million people tuning in to each episode.

It is loosely based on a real-life gang who used the same name – referring to their peaked flat caps – and the show is expected to return for a hotly-anticipated fifth series later this year.

But British-born academic Dr George S Larke-Walsh, of the University of North Texas, has published a paper claiming the show's writers use the war as an excuse to justify and romanticise violent behaviour.

The release date for series five has not yet been announced but is expected to air in the summer or early autumn on BBCOne.

BBC hit drama Peaky Blinders has been criticised in an academic paper for glorifying violence. Pictured from left are Paul Anderson, Joe Cole and Cillian Murphy as gangsters Arthur, John and Tommy Shelby, central members of the criminal gang portrayed in the show

Dr George S Larke-Walsh said the show justified the brutal violence by portraying the characters as damaged by World War One. Pictured is Murphy as Tommy Shelby

She claims the characters, including Cillian Murphy's gang leader Tommy Shelby, are all shown to be damaged by the war to excuse their criminal actions.

Dr Larke-Walsh also claims they are made out as Robin Hood-esque characters fighting for survival in a 'corrupt' world while they also use the Shelby family's gypsy heritage as a 'distraction'.

In her paper, seen by The Times, she writes: 'It [Peaky Blinders] utilises nostalgia for nationalism, enacted within displays of extreme aggression as well as promoting regressive masculine ideals ... In the current sociopolitical environment, and associated concerns about the prevalence of toxic masculinity, such presentations no longer feel safely confined to fantasy.'

The paper, titled 'The King's shilling': How Peaky Blinders uses the experience of war to justify and celebrate toxic masculinity, also suggests the show uses Murphy's naked body to 'elicit homosexual desire' but then 'asserts heterosexuality' through brutal violence.

The drama has won a host of awards and has an average audience of around 4million per episode. It has become so successful it has attracted stars such as Oscar-winning actor Adrien Brody, pictured

She added: 'There is no doubt that all audiences are meant to find the characters visually attractive. It is a feature of regressive masculinity that homosexuality must be denied.'

Dr Larke-Walsh previously obtained a PhD in film studies at the University of Sunderland before moving to the US, and has written other papers on The Godfather and The Sopranos looking at the connections between Italian-American crime families.

The producers of Peaky Blinders said the show 'invites viewers to consider the effect of violence on men, and the terrible and long-lasting consequences on both men and women of gang violence, poverty and, most of all, armed conflict'.

Dr Larke-Walsh told the times she is a 'fan' of the Bafta-winning show but wanted to highlight the 'complex nature of its depiction of violent masculinity'.