Few novels have excited as much love and devotion as Andrew O’Hagan’s Mayflies, a funny, tender but heart-rending tale of male friendship. Now, only two years after its publication, an adaptation is coming to the BBC, an astonishingly quick turnaround for television drama.

Claire Mundell, MD of Glasgow indie Synchronicity Films and Mayflies’ executive producer, has been a fan of O’Hagan’s writing since his first book, The Missing. “When I heard [Mayflies] was coming out I managed to get the manuscript very early doors, read it, and made an offer right away. I couldn’t have coped if anyone else had got it,” she told the RTS in mid-December.

“It is genuinely a classic – the quality of the writing, the tenderness of the story, [its] relevance… for a contemporary audience living in the world we are in now,” she continued.

As the cost-of-living crisis grips, the similarities between contemporary Scotland and 1986, the year the first half of the novel is set, are increasingly striking. “The two [lead] characters grew up amid the terrible economic devastation of… working-class Scotland – that affects people’s aspirations, their hopes and dreams,” added Mundell.

Having recently left school in a small Scottish town, Tully and Jimmy enjoy a magical weekend in Manchester, taking in The Fall and The Smiths, and a night at the legendary Hacienda club. Ecstatic, they make a vow to live life differently. The second half of O’Hagan’s novel is set three decades later: Jimmy’s phone rings and Tully has terrible news, and a request that will truly test their friendship.

Mayflies has been adapted in two one-hour parts by Andrea Gibb, who wrote the screenplay for the RTS award-winning BBC drama Elizabeth Is Missing, starring Glenda Jackson.

Her adaptation doesn’t mirror the structure of O’Hagan’s book; instead, it takes a non-linear approach, with extensive use of flashbacks. Earlier this year, Gibb said: “Adapting [this] magnificent novel has been one of the highlights of my career. Andrew tells his story of enduring male friendship with love, truth, tenderness and a searing humanity. There’s not an ounce of sentimentality. It’s very funny and deeply moving.”

Her script for the first of the two episodes convinced the BBC, in June, to commission the drama for an end-of-year slot. “Andrew’s an acclaimed Scottish author who speaks to a very wide readership [of all] generations – it was sort of a no-brainer for the BBC,” recalled Mundell.

Line of Duty’s Martin Compston, who plays the older Jimmy, had nothing but praise for Gibb and O’Hagan: “It can be quite a scary thing for an author to let you adapt their book and then, as a screenwriter, to let actors play with your words, but they were great collaborators and listened to all our opinions.

“When you start playing the characters you get a feel for [the drama] and you want to put your own spin on it at times, and especially so playing Jimmy. He’s a version of Andrew, and that could have been quite intimidating as an actor, but Andrew said, ‘Look, I’m here for whatever you need – ask me anything.’ He was there when you needed him but also hands off to let you get on with it. It felt from the start that we had nothing but support as a cast.”

Neither Compston nor Tony Curran, who portrays the older Tully, read the novel before the shoot; both actors prefer working to a script. “I was in Filth, and [the novel] by Irvine Welsh is one of my favourite books,” explained Compston. “There are bits in the book that I loved and I couldn’t understand why they were not in the film. So, you don’t want to get attached to pieces because you have to play the truth of the script; Andrea’s version is what we had to be loyal to.”

By contrast, Tracy Ifeachor (Showtrial), who plays Jimmy’s wife, Iona, did read the novel. “I look for the essence of the piece, and then read the script and hope the essence has been captured… Andrea did such a great job,” she said.

Curran and Compston have known each other for years; both starred in Andrea Arnold’s 2006 multi-­award-winning thriller Red Road.

Did their friendship help them play on-screen best friends? “Hugely, and hopefully it comes across on the screen,” replied Compston. “It’s always an advantage when you work with someone you trust and love… but when it’s [a drama] like this…. it’s probably the most emotionally present I’ve been in a job… it felt very real.”

Curran, he continued, is “a ball of energy… and I couldn’t imagine anyone better to play the part [of Tully] – that’s just Tony. Everyone loves being around him: he lights up a room, [he’s] very, very funny, very naive in love at times – he kind of loves everyone around him. He’s a fantastic big guy to be around and I think that just seeps into [his portrayal of] Tully.”

Mayflies also stars Ashley Jensen as Tully’s wife, Anna, Tom Glynn-Carney as the young Tully and Rian Gordon as the young Jimmy. The director was Peter Mackie Burns.

A 27-day shoot, featuring 57 locations around Glasgow and Ayrshire, followed by a rapid edit, ensured the drama would be ready for its BBC One and BBC Scotland transmission on 28 December.

But what can audiences expect? Like the book, it will offer love, laughter and tears, lots of tears. “Yes, it’s about cancer, yes, it’s about euthanasia but, ultimately… it’s life-affirming and human,” said Curran.

The essence of Mayflies, said Compston, is “friendship” and “love”, while Curran offered: “Humanity, staying in the present and being kind to each other.” For Ifeachor, the drama asks: “Are you living your best life?”

Compston hopes the drama can also achieve a wider aim: “We don’t take a side… but it’s really important that we contribute to a conversation on the subject of assisted dying, to get it going.”

Report by Matthew Bell. The joint RTS HQ/RTS Scotland event was held on 14 December, chaired by the journalist and broadcaster Paul English, and produced by the BBC’s Harriet Wilson.