There’s a scene in The Irishman where gangster Tony Pro, played by Mr Stephen Graham, sits down late to a meeting wearing a pair of white shorts, an open aloha shirt and Gucci loafers, all chest hair and swaggering, mafioso obtuseness. His lateness and his sartorial choices don’t please the neurotic and irascible Jimmy Hoffa (Mr Al Pacino), a man who prizes good timekeeping above all else, and sees a suit and tie as non-negotiable (“Who the f*** wears shorts to a meeting?”), even in the Florida heat.

But how should a respectable gangster dress, and what do his clothes say about him? How do you make a man look well turned out and also a bit dangerous? The sartorial clout of the Cosa Nostra is something that Ms Sandy Powell has learnt to replicate well. The Oscar-winning costume designer’s work in The Irishman is some of her best (if you’ve seen The Wolf Of Wall Street, Shakespeare In Love, The Favourite or The Aviator, you will already be aware of her talent).

On The Irishman, she says: “One of the first things [Mr Scorsese] talked about was the kind of guys these people are, and that it shouldn’t look too showy. But they’re still intimidating in their way, because it’s all very quiet.” The dimly lit Philadelphia steakhouse in which the characters mostly operate is an office of sorts for these men, where they talk about who’s gone too far, who’s making trouble, and who would be better off whacked (read: three bullets nonchalantly through the forehead at point-blank range).

The story is based on real people from the Philadelphia mafia scene of the 20th century, the aforementioned labour union leader Mr Jimmy Hoffa, and the titular character Mr Frank “The Irishman” Sheeran, a union official with supposed links to the Bufalino crime family. To capture them as realistically as possible, Ms Powell worked with a lot of real-life references and photographs. It’s because of this that the characters mostly dress in coolly sombre tailoring that is a departure from the boldness of mafia uniforms of Hollywood movies past. “These aren’t flashy gangsters,” explains Ms Powell. “I always think of Casino and Goodfellas as brightly coloured and remember all these pink and apricot suits and colourful ties. These guys are not that. This is a much darker world.”

“The whole point of how all of these guys are dressed is actually that they’re not showy, not obvious,” she continues. “They all have to be under the radar, especially Frank Sheeran, who is a hitman – he’s not going to want to be noticed in a room,” says Ms Powell. “Although as he gets wealthier, he gets better dressed. And with Russell [Bufalino, Mr Joe Pesci’s character], It’s incredible, because we’re used to hearing Pesci be really quite aggressive verbally, but [in the movie] he’s very mild-mannered and quiet, which is equally intimidating. So, it was about trying to capture that with the clothing, too.”

If Ms Powell found a vintage item of clothing that worked for the film, she had her tailors take it apart entirely and then remake it. “If you find an original 1960s suit that is now, what, 50 or 60 years old, the padding’s all gone from the shoulders and it looks a bit tired, so I sort of revived that by taking the padding out of the shoulders and put it all back and pretty much remade it,” she explains, “because the actual fabrics from the real period are so much better than we can get now.”

Much has been made of the suiting accessories, too, which are often the most colourful parts of the men’s outfits. “It’s all about ties with menswear like this, because that’s really the only time a man can express himself,” says Ms Powell. “Joe Pesci, for instance, always has something distinctive but not always noticeable, all the tie jewellery and tie pins and the tie clips and tie bars and collar studs and cufflinks and all of those details…”

Still, Ms Powell had more than just a few suits and tie pins to contend with. The film runs for 209 minutes, and the story spans over 50 years from the late 1940s to the early 2000s, which means a lot of trends, cuts, silhouettes and dressing norms to contend with (plus unprecedented CGI de-ageing technology to make Messrs Robert De Niro and Joe Pesci look 40 despite them both being septuagenarians). Mr De Niro alone had 102 different changes as he is seen climbing his way from a Teamsters truck driver to a hitman to a gold ring-wearing “made man” through to a disheveled and lonely retiree in a care home, from where he narrates the story. “I had to sort of divide my brain up into five different decades,” explains Ms Powell. “It was actually like doing three different films all in one.”

Despite all the lapels, ties and Gucci loafers, though, Ms Powell’s favourite look is surprising: Mr De Niro is in his wheelchair, dressed in oversized sweatpants. “When he’s younger, we had to make him look big and intimidating, because the real Frank Sheeran was a bigger man than Bob De Niro, so we tried to do things to help with that. But by the end I wanted him to look smaller and withered away. And I think there’s something about those track pants that are really funny.” That look was actually based on a real photograph of Mr Frank Sheeran, complete with the Teamsters baseball cap he continued to wear. “He would have kept that all of his life, loyal to the Teamsters to the bitter end.”

The men featured in this story are not associated with and do not endorse MR PORTER or the products shown