Thirty-seven years ago, when Paul McGuinness signed a virtually unknown teen rock band called U2, he was also interested in making movies. After dropping out of Trinity College Dublin, he'd worked on John Boorman's classic film Zardoz and made television commercials.

“If I had a career plan at that time, it was to be either a film producer or the manager of a giant rock band,” McGuinness recalls in the sun-flooded livingroom of his home in Notting Hill, surrounded by his collection of Irish paintings.

Life doesn't often give one the chance to go back and take the other fork in the road, so when McGuinness retired as U2's manager in November 2013, he welcomed the opportunity to produce movies. He realised that "this is the golden age of television drama," that pay television now attracts the creative talent and money. He recruited the best: director Neil Jordan and writer John Banville. The three have worked for the past year on a crime drama series for pay television, titled Riviera.

“It’s about a sort-of French, sort-of Italian business family,” McGuinness explains. “This large, seemingly legitimate family business empire conceals a criminal enterprise. That’s the basis of the story.

“Everyone in the world goes to the south of France when they make a bit of money,” McGuinness continues. “U2 and myself were the same when we all acquired houses there 20 years ago. Nowhere in Europe is more than two hours away. The tour plane would go back to Nice after the show, and you got to sleep in your own bed.”

The British writer Somerset Maugham described the Riviera as “a sunny place for shady people”. (As McGuinness points out, the quote is often mistakenly attributed to Graham Greene or F Scott Fitzgerald). Over the past century, the Côte d’Azur evolved from a winter resort for European royalty to a summer gambling and yachting paradise for the rich and famous.

“From a dramatic, story-telling point of view, it’s perfect,” McGuinness says. “You can legitimately cast any type of person from anywhere in the world and believably locate them in the south of France. You can have them misbehave, fall in love, whatever.”

McGuinness has received an enthusiastic response from potential investors. Based on Netflix's House of Cards, he expects production costs to total between $40 million (€36.7m) and $50 million (€45.8m) for each 10 to 12-episode season. He hopes to see Riviera on air by the autumn of 2016.

Jordan and Banville have spent weeks brainstorming with McGuinness in the villa he shares with his wife, the publisher Kathy Gilfillan, at Èze-sur-Mer. "We're 'roomies' in Eze," McGuinness jokes. "I'm the butler and driver." Having recently written and directed 30 hours of The Borgias for Showtime, Jordan is the "show runner," in creative control of the project.

The three Irishmen are consulting crime journalists and lawyers in France. They've befriended David Chase, the creator of the wildly successful Sopranos series which started the trend in the US.

Most European governments attract film production by reimbursing a percentage of costs. France is about to move to a 30 per cent refund system, which will help to offset the higher costs of shooting there. McGuinness intends to centre post-production work in Ireland, where section 481 of the tax code gives film production a 32 per cent credit.

Bringing part of the Riviera operation to Dublin is consistent with McGuinness's record. Before McGuinness and U2, Irish artists had to go abroad to succeed, says Bill Whelan, the Riverdance composer and McGuinness's partner in McGuinness Whelan Music Publishing. "U2 reversed the tide. People stayed in Ireland, were managed out of Ireland, and record companies began to come to Ireland to look for talent."

Had it not been for the Windmill Lane studios, U2 and McGuinness, Whelan continues, “We wouldn’t have the Hozier phenomenon today. They created a self-confidence that injected something very important into our zeitgeist. Paul was an integral part of that.”

When he met U2, McGuinness was managing a band called Spud. “They were in their mid-20s, like me, and they had responsibilities and families and children,” he recalls. “They were not ambitious enough to go all the way. I had my eye out for a band that might go all the way.”

Bill Graham, the late journalist with Hot Press and McGuinness's friend since Trinity, suggested he check out a group called U2 at the Project Arts Centre.

McGuinness found was he was looking for. U2 became one of the most successful bands in history, selling 150 million records and winning 22 grammy awards. The 360° tour, from 2009 to 2011, was the highest grossing concert tour of all time, bringing in €653 million.

Now U2 are on the road again, without McGuinness. When he sees the iNnocence + eXperience tour in Chicago, it may be a bittersweet experience. He and U2 parted amicably in November 2013. "When McGuinness started managing U2, they were callow teenagers," says Michael Ross, a journalist who covered U2 extensively. "By the end of it, they were global stars."

McGuinness says relations between five men who worked together for 35 years are by definition “complex”, that he is closest to Bono and Adam Clayton. “I’ve had as much advice from Bono over the years as he has from me. It’s that kind of relationship, based on respect, fuelled by success and achievement.”

Choosing his words carefully, McGuinness continues: “I think we were all pretty clear that it was time to end it . . . We were coming up to another campaign. They tend to last five years from the release of an album to the end of a world tour. It seemed like a good time to draw a line. It was always understood that I would stop before they did, because I’m 10 years older.”

McGuinness shrugs off rumours about the circumstances of his departure. “There’s a tabloid newspaper hunger for Bono stories in Dublin,” he says.

His loyalty to U2 continues.

"I'm very fond of them, to differing degrees. I sometimes miss my clients. What I never, ever miss is having clients. We had our protocols. There was quite a lot of etiquette. We were quite formal in our dealings with one another."

McGuinness will turn 64 on June 16th – Bloomsday, as he points out. “For many years, I had an agenda every day. There were always things to complete. Though I was in charge of my own timetable, there always was one. I now occasionally wake up and say, ‘What do I have to do today? There isn’t anything that I have to do.’ I like that. But I’m not retired.”

When U2 first went on tour, they squeezed into a van with their equipment. They graduated to a bus, and eventually to private jets. McGuinness “approached the music industry as a kind of Darwinian project”, says Michael Ross. “For him it was survival of the fittest. He drilled the band to be match-fit.”

McGuinness laughs when I ask about the “Darwinian project”.

“There was a long history of artists making bad deals and being exploited and ending their lives and their careers in poverty,” he says. “We were not meant to be part of that pattern. We decided to be as good at the business as we’d be at the music. That was something the band and I very much agreed from the beginning. It became second nature.”

McGuinness notoriously enjoys good company, food and wine. “There’s an enduring Paul McGuinness myth that we booked tours around the great restaurants of Europe,” he laughs. “It’s not quite true, but there’s a grain of truth to it . . . The band observed with amusement that very often the gigs we played were close to a good restaurant.”

McGuinness is cautious of nostalgia. "Inevitably, you colour your recollections," he says. "I remember a conversation with the band in which someone said, 'That's what happened,' and someone else said, 'No, that's just what we decided to say happened'."

In the early years, he admits, it came as a shock to him that three of four band members (except Adam Clayton) were born- again Christians and members of a Bible group called Shalom. “I think you can see it in the lyrics,” he says. “They have religious beliefs that I never particularly shared, or didn’t share at all.”

McGuinness recalls humouring U2 parents who were “not all wild about the idea of them not going to college. Bono and Edge were both university material. It’s fair to say the other two were not. All the parents were concerned about them being in a punk band . . . I told them I couldn’t guarantee this was going to work out, that it was a risky business, but I was going into it on the same basis and took those risks with their sons. It was a middle-class discussion.”

McGuinness is “enormously proud” of Alexandra and Max, his children with Gilfillan. Alexandra is now a Los Angeles-based independent film producer, while Max, a doctoral candidate at Columbia University, is currently walking in Samuel Beckett’s footsteps at the École Normale Supérieure in Paris.

“The house was always full of books and records and the people who made them,” McGuinness says. “It’s good to grow up in an environment where that is regarded as normal. Both our children have a deep love of music, literature, movies, theatre, and in Max’s case, politics and economics as well.”

One high moment occurred in the summer of 1985, when Bono and his wife, Ali, joined McGuinness and Gilfillan at a home they rented near Venice. "One sunny day, Bono came down to the pool with his guitar and played I Still Haven't Found What I'm Looking For. It was clearly wonderful, and going to be huge."

In 1987, that song, and With or Without You propelled the Joshua Tree album to the top of the charts worldwide. Time magazine's cover story declared U2 "Rock's Hottest Ticket". Much champagne was drunk. The ageing Frank Sinatra plucked Bono out of the audience at his Las Vegas show to praise him. They later recorded a duet together, and Sinatra asked Bono to make a speech when he received a Grammy award for lifetime achievement.

“After the mid 1980s, the records started to go to number one everywhere in the world, every time . . . The sensation was not so much of celebration as just relief,” McGuinness says. “It was a feeling of ‘Okay, that was supposed to go to number one. It would have been really annoying if it hadn’t’.”

U2’s relationship with Irish media changed, McGuinness says. “It was a bit like having a national football team that won the World Cup every four years. After you’ve done that four or five times, people say, ‘Yeah, of course they did.’ It became routine. The coverage became jaded.”

Bono’s status as an artiste engagé was criticised. “He’s a man of strongly held views, political and religious,” McGuinness says. “They’re kind of intertwined for him. He is a committed, activist Christian.”

Bono won a major lobbying victory when he persuaded the George W Bush administration to reverse its position on financing antiretroviral drugs to fight Aids in Africa. The Christian right had blocked it, so Bono befriended the late, right-wing southern senator Jesse Helms.

“I had to babysit Jesse Helms at a concert,” McGuinness recalls. “He told me, ‘That young man (Bono) certainly knows the scriptures.’ Bono had wrangled him. The Bush administration started to spend billions on antiretroviral drugs.”

U2 also campaigned against the 1992-1996 siege of Sarajevo, during which nearly 14,000 people were killed. After the siege, the band were the first to perform in the olympic stadium that had been used as a cemetery.

During the siege, the US aid worker, writer and director Bill Carter brought residents of Sarajevo into a studio for live satellite link-ups with U2 concerts.

"We were heavily criticised for exploiting people's misery," McGuinness says. "There were three girls from Sarajevo on camera in the middle of a concert at Wembley stadium, and they said, 'This American guy told us you are all in London having a good time at a concert. We are not (italics) having a good time. There are people shooting at us.'"

“We stopped doing it after that,” McGuinness recalls.

McGuinness had persuaded the band to split everything five ways at the outset, though his share was later reduced. “At the beginning, I said, ‘Look, there isn’t going to be very much money, so let’s just split it equally to avoid problems’.”

U2 signed with Island Records in 1980. Success came three years later, with the War album and two hit singles, Sunday Bloody Sunday and New Year's Day. The Unforgettable Fire followed in 1984, with Bad and Pride (In the Name of Love).

Island Records couldn't pay the royalties for Unforgettable Fire. Rather than sue and destroy the company, or take the subsequent The Joshua Tree album elsewhere and end up in a nasty legal battle, McGuinness had the patience and foresight to take a 10 per cent share in Island for the band and himself. It was one of his greatest coups. As Gareth Murphy recounts in Cowboys and Indies: the Epic History of the Record Industry, Island was sold a few years later to PolyGram for $300 million (€275.1m) .

When they parted in 2013, U2 paid some €30 million for McGuinness’s Principle Management company, in a deal financed by the giant concert promoter Live Nation. The amount is a matter of record, McGuinness says.

The Sunday Times 2013 rich list estimated U2's collective wealth at €632,535,925. "I have no idea how they get these figures," McGuinness laughs. "We have never confirmed or denied any of them. They are sort of made up."

Over lunch of gravadlax, sea bass and Viognier wine at the Chelsea Arts Club, I ask McGuinness how he would respond if I posed that vulgar American question, “How much are you worth?”

“That’s not a question I would answer,” he says with good humour. “I don’t think it’s polite, really, to talk about things like that. There’s a question of privacy. I don’t think anyone’s entitled to know.”

He has invested much of his fortune in the beautiful homes he bought with Gilfillan in Ireland, England and France.

McGuinness defends U2’s controversial move of one of their companies to the Netherlands in 2006. Irish critics have portrayed the decision as being at odds with U2’s commitment to social justice.

“First of all, I don’t give U2 tax advice. I never did,” McGuinness says. Nor was the move precipitated by Ireland lowering the threshold of the tax exemption for artists. “It was happening anyway,” he says. “There is an expertise in Holland, a particular accounting practice that is used by the Rolling Stones, that specialises in the collection of royalty income on a worldwide basis . . . That was the real reason for it.

“U2 pay tax in every country in the world,” McGuinness continues. “You can’t just turn up in Germany, play a gig and take all the money. There’s a lot of laziness about the way this is covered.”

Objections to U2 not paying tax in Ireland are “meaningless”, McGuinness says, because “their Irish income is taxed, but they also give it away.” For example, the €5 million profit from U2’s last Croke Park concerts was used to establish the Music Generation programme for teaching music in Irish schools.

Last September, U2 were criticised for launching their Songs of Innocence album with Apple, through an automatic download into half a billion iTune accounts. Commentators said the band would not have done it if McGuinness had still been their manager.

“Who knows?” he says. “I wasn’t involved . . . They apologised for it afterwards, saying it was an imposition. I think it was positioned wrongly. If they’d made it ‘tick this box and you can receive the U2 album’, it would not have given offence. People were unhappy about having something arrive that they hadn’t asked for. It was easy enough to delete . . . But I think that it should have been handled differently.”

The music industry McGuinness left in 2013 was almost unrecognisable. Internet downloads and streaming destroyed CD sales, and live concerts have become virtually the only way to earn money.

“The record industry prepared very badly for the digital age,” McGuinness says. “In the 1980s and 1990s, there was a boom in income from CDs. Artists and record companies made a great deal of money and they thought it would continue. They prepared clumsily for the onset of digital. There was an encryption system called the Secure Digital Music Initiative that was supposed to prevent copying. Of course it did not.”

McGuinness’s outbursts against the internet giants who’ve made billions at the expense of musicians and record companies went unheard. Today, Spotify streams music legally, he says, “but the royalties are so infinitesimally small as to be meaningless. That’s a debate taking place across the music business.”

Bill Whelan speculates that the corporate invasion of music left his old friend McGuinness feeling “like a stranger in a strange land”. Asked if he’d feel at home in today’s music industry, McGuinness replies, “I don’t think I would. I’m curious, but I’m not really involved, except as a spectator and sometimes as a commentator.”

McGuinness may have abandoned music for television drama, but his 35-year management of U2 left an indelible legacy. “He’s one of the top five managers of all time,” says Richard Griffiths, the manager of the boy band One Direction. “And above all, Paul McGuinness is a nice man.”

Paul McGuinness will be interviewed by David McWilliams at the Dalkey Book Festival on June 13th.