It's a book that is imbued with the essence of Glasgow so there was no doubt about where to film The Long Midnight of Barney Thomson when plans to turn the horror comedy into a big screen blockbuster were announced.

Written by Douglas Lindsay and previously serialised by HeraldScotland, the story, which is the first of seven books, tells the tale of Barney, a barber whose mundane life gets turned upside down when he accidentally becomes a serial killer.

The big screen adaptation, which is financed by Creative Scotland and Telefilm Canada, features a stellar cast including Robert Carlyle, who will also be directing the film, Emma Thompson, Ray Winstone, Ashley Jensen, James Cosmo, Martin Compston, Sam Robertson, Tom Courtenay and Eileen McCallum.

However, as he prepared to rehearse scenes outside the city's iconic Barrowlands, producer Rich Cowan said that Glasgow was one of the main stars of the show.

Cowan, who has also co-written the script for the film with a huge input from local writer Colin McLaren, said in an exclusive interview: "Glasgow is one of the film's main characters - if Barney is character one then Glasgow is character 1A.

"The movie is about the city and the people. A lot of people film in places because of their beauty and not because of the texture they add to the film but we're filming in Glasgow because it adds a texture to our story."

The entire film is being shot at locations across the city in 28 days, with the East End providing a home for the barber shop that Barney works in and the Barrowlands doubling as a bingo hall for scenes starring Carlyle as the downtrodden lead and Thompson, who plays his mother Cemolina. Other real locations being used include Shawfield dog track, a Cumbernauld loch and Tollcross.

Cowan added: "It's been awesome filming in Glasgow because it is a barber town. We were filming in Bridgeton and there are four or five barber shops near our location, it's something you don't really see anywhere else."

Although remaining true to the book, the title has been changed to The Legend of Barney Thomson for the big screen and the role of Cemolina has been expanded to give a greater insight into her background, a decision which helped entice Emma Thompson to take on the role.

Thompson's transformation into Cemolina, complete with Glaswegian accent, takes three hours and is carried out by Mark Coulier, who has worked on the Harry Potter films, X-Men and won an Oscar for The Iron Lady. Her look for the film was officially revealed yesterday.

Cowan said: "Cemolina's role is very confined in the book so we've expanded it for the film. We will see more of her background, what she's like and what she gets up to. We'll see her at the dog track and the bingo. She's a real woman about town.

"When Emma read the script she said she wanted to do it straight away. She's nailing it at the moment."

However, Cowan is determined to remain true to the essence of Lindsay's original story.

He added: "The movie has to be Barney made a terrible wish and it's coming true. We have had to adapt some roles but the story had to stay the same and it has.

"It's set in no time, we're not suggesting it's not 2014 but you won't see anyone on a cellphone. The bus that we're using in the scene we're shooting outside the Barrowlands is new but Barney's car is 15 years old. We're trying to show that there are different worlds within this story, Cemolina's world is this, Barney's is this and the police world is more modern."

Cowan has been working for seven years to bring the project to the big screen after being introduced to the book by a friend and said that Carlyle's love for the story has helped to make it a reality.

He said: "Bobby is a son of this city and people are pleased to see him.

"For Bobby this is a movie about his home town, it's built into the fabric of the city he loves. He's very well connected and when you start a movie it's all about relationships. Bobby's relationships are very deep and he showed it to people he wanted to get involved and that definitely helped bring Ray Winstone and Emma Thompson on board."

Carlyle is also determined to make sure that his directorial debut remains true to Lindsay's original tale, telling the author on set: "I hope we do it justice, I hope we make you proud."

Lindsay, who also writes indyref blog The Shackleton Report for HeraldScotland, said: "It's great to see my book made flesh, I'm very happy.

"I wrote it while basking in the sun in Senegal so that may be why Glasgow's dreicher in it but I like the fact that it's being filmed in Glasgow."

The film is scheduled for release next year.