WC FIELDS once wisecracked, ‘If at first you don’t succeed, try, try again. Then give up.’ It was a neat twist on the proverb, but when chatting to Sir Cameron Mackintosh you seen realise Fields’ gag is anathema to his very being.

The world’s most successful theatre producer is back in Glasgow this week to open Les Misérables, his theatre classic which, to date, has been seen by 120 million people across the world.

But those who don’t know Cameron Mackintosh may wonder why. The Covid impact of the past two years has left theatres darker than Phantom’s catacombs. And any normal 75-year-old billionaire who owns eight West End theatres surely would have decided enough is enough and stayed at home to watch Hairspray on Netflix.

However, that’s far from the case. Indeed, Mack is back in town with a vengeance. “It’s the most concentrated period of my life,” he says. “Les Mis is my seventh show I’ve opened since July, right across the world. In fact, I’m supposed to be getting on a plane at the weekend, to open Miss Saigon in Vienna.

"But as we all know, Vienna has shut down for a month, so we won’t know for 10 days whether we will get to open.”

He offers a hint of a sigh. “It would all be a huge amount of work to do in normal circumstances. But with Covid, it’s been a nightmare. I hope I never have to go through all that again.”

The producer offers up a hint of the current complexities in trying to make theatre happen. “The key creative staff there [in Vienna] is a core of people. And you only have them contracted for a short period because they are due to go on to another show. So, you’re worried about that. Then you’re worried about the actors getting Covid, and you’re worried about the audience. But having said that, the audiences have been incredibly supportive. They’re coming in.”

Mackintosh’s Les Mis is selling so well he doesn’t really have to promote the show. But you sense he wants to herald its return. And why shouldn’t he? The producer lives to make theatre. He lives to watch rehearsals, check out the fine detail, check the lighting and sound; making sure his French revolution tale is an exercise in theatrical perfection. (He once described himself as ‘An interfering b******.’)

“We have a wonderful cast for this six-week run,” he enthuses. “I wish we were here for 10 weeks because I’m sure we could sell it out.”

He adds: “One of the few pluses to come out of Covid is that the public seem more aware of what goes into creating a theatre show. What seems effortless takes a huge amount of effort. I think they appreciate what we do.”

But what of the weight on his shoulders? It’s hard enough being a theatre producer with shows running around the world without having to contend with continuing disasters.

“What I’ve had to do is keep the business going. And it’s been very, very hard. I’m unique in that I’m not owned by a hedge fund. I don’t have outside investors. By and large, I am my own boss and I have to employ people to run my theatres and shows. The truth is all my theatres and shows around the world were doing incredibly well, then suddenly we found that a lot of trains were suddenly hurtling into brick walls, globally.”

His voice becomes darker. “Commercial theatre in this country has had virtually no support from the government, apart from rates relief, or furlough. But most people who work for us are freelance, so they’ve fallen out of that net. It’s all very different to the likes of America and Australia and Japan who recognised that theatre is the heart and the soul of the country, but also the economic drivers.”

How did he feel when Culture Secretary Nadine Dorries said recently that commercial theatres didn’t need cash injections from the Commercial Relief Fund, and the fact they are still standing is proof of that fact? “Did she say that? Well, nothing this government says would surprise me although we are hoping the Chancellor will at least help us with a tax break to get us through this winter, to get these big shows back up.”

He takes a moment to reflect. “I’m proud of people who work for me. So many actors have had to take on other jobs. My actor who plays Valjean in Les Mis has been out driving a truck and going around Tesco's. It’s been humbling. We’ve also lost around a third of the people who would normally work in theatre. Some have decided that the job they took to keep their livelihoods going suits them better now.”

Mackintosh reveals that as well as losing many creatives and backstage people, he’s lost a significant number of actors. “There are so many TV series being made everywhere, with the likes of Netflix, and we’re losing so many of our character actors. Amazon have four or five big studios operating in Britain right now. And the knock-on effect is that theatre is being drained of talent.”

Yet, true to form, the producer is turning the problem on its head. “What’s exciting about this [Les Mis] company is that there are three people who haven’t been at drama school, playing younger characters. Because I’m involved with the Conservatoire in Glasgow, a lot of the students are doing workshops with my company during the run of the show.”

For any young person considering a life in theatre, Cameron Mackintosh is an exercise in the power of passion and determination, to be part of great theatre. Ever since an aunt took him along to a production of the musical Salad Days in 1954, the seven-year-old was entranced by the stage and hasn’t stopped wanting to create theatre ever since.

At school, the young Cameron, (his father was Scottish) was nicknamed Darryl F Mackintosh, in a nod to the legendary Hollywood mogul. Aged 19, Mackintosh landed work on Oliver! as an assistant stage manager, while also playing the role of a Pot Boy. Years later, he still has the poster from the show – ‘To Cameron, the man who gets things done,’ scribbled by an actor in the production.

Yet, early attempts at producing shows were disastrous. One of his first, Anything Goes, in 1969, lost £40,000 in unsecured loans and another, Home with the Dales, lost £10,000 “because no one wanted to see it.” He produced yet another turkey in After Shave, which he’d hoped would be a female Beyond the Fringe.

Try, try again? Thankfully, he did. Mackintosh was still living in a £5-a-week rented flat in 1980 when, at the age of 43, he met with chum Andrew Lloyd Webber for lunch to discuss an idea. The composer reckoned a musical could be written based on TS Eliot poems. “We went back to his flat and he played me some of his settings of Old Possum’s Book of Practical Cats and I went, ‘Oh, there’s something there.’”

The producer’s resilience had won out. But you also need the instinct to spot a great idea, know the component parts of theatre intrinsically, or be prepared to wrestle for years for the rights to stage Mary Poppins.

And it helps to have the thrust to grab onto Hamilton, which he hopes will come to Scotland in two/three years. Mackintosh, who has a home at Loch Nevis, laughs as he points out; “Of course, Alexander Hamilton came from Nevis, before being sent to America. So, Hamilton is really a Scottish musical.”

It’s fitting Cameron Mackintosh has returned to Glasgow with Les Mis, the ultimate show of defiance. Mackintosh speaks at some length about how young people represent great hope for the theatre future – his new venture Mountview, a fantastic new facility in London offers, he says, people of every race and background the chance to come through and get first class training.

“When Andrew and I started to do Cats, we had to audition for months to find people of the standard we needed. Now, 40 years on, London can run 30 musicals at once.

“Finding black performers was difficult when I first did Five Guys Named Moe. Now, there are many wonderful black and Asian performers out there.”

He adds: “You need the work to attract the people. And the more successful a show is the more you have to bring in new talent to feed it.”

A show such as Les Mis? “Yes. It’s a great musical but it has such a social resonance, and it never dates. It reminds there are always people out there fighting for a better tomorrow.”

His smile alone suggests a forward momentum that is almost uncontainable. “And thankfully this show proves that tomorrow always comes.”

Cameron Mackintosh’s, Les Misérables, Theatre Royal, Glasgow, 23 November - 31 December