The email was from Rafael Nadal’s PA. He had heard about the portrait and he just had to have it.

The artist was widely renowned and the Painting, entitled Rafa, would be perfect for a blank space on the walls of his tennis academy in Majorca. Could we oblige?

It was a pinch-me moment. I’m a huge tennis fan and one of my sporting highlights was watching him win his tenth French Open title in Paris. And he was interested in one of our pictures — one that had been painted just feet from where I sat. Seriously?

With its bold red, black and yellow colours, it was a very striking piece of art, and within hours it was on its way to its new owner.

But there was something else extra special about the picture: the painter was a pig.

Yes, you read it right. A pig that can paint. A pig named Pigcasso.

I guarantee that the story of this astonishing farmyard animal’s journey from slaughterhouse to artistic superstardom is one of the most extraordinary you’ll ever hear.

Pigcasso came into my life with her sister Rosie in the summer of 2016 soon after I’d opened the doors of my animal rescue centre for the very first time.

Exhausted and with their tails docked, the two little creatures had never even been able to lie down properly at the factory farm where they had been reared. The next stop for them would have been the abattoir. So their first night on a bed of luscious hay must have been the best sleep of the rest of their lives.

One was gentle and inquisitive with a healthy appetite. The other was more dominant and obsessed with hoovering everything up, with or without nutritional value: dust, flooring, gates, iPhones, you name it.

Although I was no expert, I knew that pigs love to play even more than dogs. I tried to encourage their sporting skills with footballs, rugby balls and Frisbees. It was a disaster. Rosie ate or destroyed everything within a few minutes, blowing her lifetime budget for playground toys in a single day.

The other little pig, who was as yet unnamed, was better behaved but still ended up doing what most pigs do: chewing everything within a trotter’s reach. With one exception. The builders who had been working on the sanctuary had cleaned up when they finished but had left behind an old paintbrush, which I casually chucked into our play session one day.

The little pig nudged it, then picked up the brush in her mouth. For 20, maybe 30, seconds she just stood there as if to say: ‘What next?’ Then she gently dropped it.

That was the day she got her name. I toyed with others, including Francis Bacon and Vincent van Trough. But there was only one it could possibly be: Pigcasso.

But I couldn’t help wondering: if the pig could pick up the brush that gently, with intent, was it possible she could actually paint? It would certainly keep her entertained. I knew it was a ridiculous idea. But no matter how hard I tried to forget it, Pigcasso wouldn’t let me. She spent an inordinate amount of time gently playing with that paintbrush.

Like a chicken and its egg, she protected it from harm and defended it from Rosie as if her life depended on it.

I spoke to an animal behaviourist friend. She clearly thought the concept of a painting pig was crazy, but confirmed what we both knew: that we were dealing with a highly intelligent creature who was naturally curious, so who knew what was possible? We could only try. I began by designing Pigcasso’s paintbrushes, as they needed to fit comfortably into her mouth. I taped a couple of empty loo rolls to a brush’s slender wooden handle, then covered it with the kind of foam you’d use to regrip a tennis racket handle. Hmmm. Not bad.

I placed a few brushes in her stall, stood back and held my breath. There was always a risk she’d treat them like tortillas but, to my delight, she picked one up. Holding it firmly in her mouth, she shook her head from side to side and then up and down. I was biased, like any proud mum, but I felt we were off to a flying start.

In our local art shop I filled a trolley with a few small canvases, an adjustable easel and a selection of non-toxic paints. In no time, the sanctuary transitioned from barn to artist’s studio. Not just any studio, either, but a painting pig’s studio. The only one in the world.

It turned out that picking up the brush from a pot of paint came naturally to Pigcasso. Getting her to dance it across a canvas took a bit more time. But, incentivised by a few grapes and subjected to a series of one-on-one lessons involving me on my hands and knees crawling around her barn with a brush in my mouth, she caught on pretty quickly. And once she had that paintbrush it in her mouth, the results were magical.

For weeks and months Pigcasso pressed on. She wielded the brush with unbridled enthusiasm, her head moving frantically in all directions. Her designs were at first pretty random, lacking any sense of structure, form or flow. But as she grew, her artworks did too. Was it just my imagination?

Absolutely not. The shadows were becoming shapes: swirling, joyous, heart-lifting shapes. There was order emerging from chaos.

And then on one particular morning she almost hesitated, standing in front of the canvas before making a few strokes in black paint. And then she stopped. It was obvious to me that I was looking at something truly special, even if I couldn’t quite define it. It was very, very pleasing to the eye, a picture I’d have paid good money to own.

It was then that the brainwave struck me. Maybe we could sell some of her artworks to keep the sanctuary financially afloat?

I wanted to rescue a cow next, chickens after that, maybe a goat, definitely more pigs. But I knew that with all the vet and food bills I couldn’t afford it. A kind friend had given me a loan to set up the centre but we needed a revenue stream other than people’s kindness and charity.

I had no idea what her paintings would, or could, be worth. A few pounds? Anything at all?

I consulted Harald, the friend whose extraordinary generosity had helped me get the sanctuary going. He was a shrewd entrepreneur, as well as an art and animal lover. ‘Price them at whatever you want,’ he told me. ‘If none sell after three months, double the price!’ As it turned out, I didn’t have to make that decision. A few days later, two American visitors to the beautiful area of Franschhoek, near Cape Town, where I live, turned up and asked if they could see the wonderful painting pig.

They were fascinated by our story and asked if they could buy one of Pigcasso’s artworks. ‘How much?’ they said. Caught totally on the hop, I didn’t know what to say.

‘Make an offer,’ I said.

‘Five hundred dollars?’ Done! That would be enough to sustain the sanctuary for weeks.

After that, things moved fast. I decided that when it came to my genius pig’s colour selections, I needed to lend a hand.

Unlike humans and several other primates who have trichromatic vision, pigs have dichromatic vision. Unable to differentiate red-spectrum light, their colour perception is limited.

Not only that, I also needed to stop her, after she’d painted a beautiful shape, completely covering the page in her enthusiasm for more. From now on we would be a partnership, an artistic collaboration. It was a defining moment, and we never looked back. As Pigcasso painted, I would watch from a distance. If I saw something interesting unfold, I would make a sound with a simple clicker. This was the cue for her to drop the brush and step away from the canvas. She got the hang of it at once.

Then, while she was rewarded with a few grapes and other treats, I’d decide what colour or positioning of the canvas would come next. And so it went. Sometimes I’d click after a second, other times, I’d let her rock ’n’ roll.

If I moved the paint pot further to the right of the canvas, she’d focus her strokes in that area. If I turned the painting sideways or upside down, I could get her to paint in a whole new section.

The most intriguing