If you have never heard of José-María Cano, you probably aren’t Spanish or a divorce lawyer. “In the Spanish world,” this musician-turned-artist says of his 1980s pop band Mecano, “we were equivalent to ... probably ... the Beatles.”

We’re sitting in an enormous house in Holland Park, West London, of the sort that might belong to a hedge-fund manager or the man who invented the paperclip. Cano bought it 16 years ago, at the height of his pop success, from the manager of Duran Duran.

On the walls are examples of his art. From today, the Riflemaker Dairy in Bloomsbury plays host to The Wall Street 100, Cano’s series of 100 large wax portraits of corporate and financial figures, taken from those tiny portraits you see in articles in The Wall Street Journal. Some you’d recognise (Bill Gates, Roman Abramovich) but most you probably wouldn’t. His own favourite is Bernie Madoff. “It is my best,” he says. “It was what Madoff was born for. I will always be grateful to him.”

For all that, he doesn’t consider them portraits. “I don’t like the idea of paintings getting out of the group,” he says. “This is a point of view of what are successful people. The Wall Street Journal view.” Being wax, they are more like sculptures than paintings. The surfaces have a translucent depth, and the markings look raised; you want to run your fingers over them. Wax, though, is the stuff of candles and deathmasks; the effect is often quite gruesome. This is not a tribute, more a horrified study in iconography.

Cano has another series of portraits called The Wall Street Wax Museum, which is more about fame — celebrities and politicians. The day before we meet, his version of the Queen has sold at Sotheby’s for £61,250. Recently his Barack Obama was given as a gift to the President. Each portrait takes him about three days. He works and works and works.

“I don’t like to be a dilettante,” Cano says. “Nothing really entertains me. Either it passionates me, or it bores me.” His English is perhaps less fluent than he realises. This makes his speech a bit like his work. Up close, it can seem a bit of a mess. From a distance, though, the message is clear.

The work habits are a hangover from his days as an international pop star. “There were days when we were doing three different things in three different places: TV in Paris, getting a prize in Barcelona and playing that night in Bilbao. It never stopped.”

It’s an odd experience, meeting somebody fabulously famous of whom you have never heard. From his late teens onwards, Cano was one third of Mecano, with his brother Nacho and the singer Ana Torroja. They were huge across Spain, Latin America, France and Italy, alternative but also mainstream. Penélope Cruz first came to fame in one of their videos, and used to date Nacho. In total, they sold about 25 million records. When I ask Cano if he could casually walk down a street in his native Madrid, he just smiles.

Possibly this is why he lives in London. It must have been odd for him, nonetheless, entering the art world as a virtual unknown. Much of his work is almost cynically self-referential. Alongside the portrait of the Queen at Sotheby’s, he had a small show called God Sell the Queen, which was a stage-by-stage imagining of that very portrait being bought at auction by François Pinault, the owner of Gucci. “The most important artists in the last century were the ones who were most concerned about the market,” Cano has said.

He was born in Madrid in 1959, in what he calls “Franco time”. He was one of four. His mother studied politics, and his father was involved in bullfighting before running a clothing business. In Franco time, Cano says, “nobody had ever seen a nude woman, so I was drawing nudes when I was 10”. He had a passion for art, but he never expected to make a career out of it. Instead, he was studying to be an architect, like his eldest brother. Before that could happen, though, he, Nacho and Torroja, his girlfriend at the time, started a band.

“Many people have a band,” he says, “to drink beer and play somewhere. We were the same. It was just very successful. I never knew how to play an instrument or anything, then it succeeded, so I learnt.”

Domestically, Mecano rode the cultural wave of newly democratic Spain. Overseas, it was different. “If you are No 1 in England,” he says, “like this girl Winehouse, she gets worldwide immediately. We were like a local artist everywhere. So we had to go touring. South America, Mexico, Peru and Ecuador. All the French-speaking areas. And Holland.” Eventually, he says, “I felt that whatever I was going to do, I had done already, many times. My brother was very Mick Jagger, but I never liked [it] within that world.”

Towards the end, things were complicated. His marriage to the former stewardess Marta Gomez Visedo was disintegrating, and their son Dani (now 13) had just had Asperger’s syndrome diagnosed. “I didn’t know what that was,” Cano says. “We were going to make a very long tour and he was 3 years old. And it was exciting that he was a different sort of person and I had to understand that. [So] I left my band. I didn’t even tell people why. Everybody was shocked. Especially the record company. It was ... fantastic.”

His divorce was long and grim. His wife was represented by Fiona Shackleton, who had represented the Prince of Wales. “I could not work,” he says, “because I would be asked for 270 invoices, or do you own the recording studio where you are working? Or are you having a relationship with the recording technician? When you are in a divorce you should do nothing.” So he started painting.

At first, it was merely therapeutic. When he received a letter from his wife’s lawyers — complaining about his behaviour, or insisting that he must no longer be allowed unsupervised access to his son — he would cast it in wax, huge. “If you paint that and put it on the wall,” he says, “then you control it. You hang it. Like when they were hanging [the corpse of] Cromwell.”

His pictures were hanging in his house when a chap called Craig Robins called round, with a young woman called Ambra Medda, to see his art collection. Robins is a developer, who was in the process of transforming downtown Miami. Medda was soon to become the director of the international design fair Design Miami. A few days later she contacted Cano and asked him to put on a show. He was an artist.

Cano talks about his work with the wild enthusiasm of a convert. He will take you up close to show you the air-brushing and the bits that are actually pink or blue but which serve to create a black and white effect. He will show you this window sill, which isn’t to scale but looks, from a distance, as though it is, and that face, which he is proud to have made recognisable, despite it just being made up of four dots.

He acknowledge that he owes a debt to the original WSJ artists, “but I don’t know who they are”. Of all the portraits, only one — of Martin Luther King Jr — was in any way signed. It had the initials “HB” in one corner, so his version does, too.

Since our interview, one illustrator, Noli Novak, who first created that image of Obama, has accused Cano of plagiarism on her blog. This is tricky ground. He points out that you have to do quite a lot to a bit of newspaper to make it still look like newspaper when it’s two metres tall and wax. You might as well say that Andy Warhol plagiarised his Brillo Boxes.

“When people are old, they end up painting landscapes,” he muses, as we descend the stairs beneath the gaze of bankers and captains of industry. “I suppose it is very relaxing. It was always more natural for me than music. But I could never have done it in Spain. I don’t have an art career there at all.” There, poor chap, he will always be just a multimillionaire chart-busting pop star.

José-María Cano: The Wall Street 100 is at Riflemaker Dairy, WC1 (www.riflemaker.org), from today until Dec 5

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