Andy Warhol, Amy Winehouse, Pop Art and the Black Isle: the life of artist Gerald Laing as told by his son

Amy is too busy kissing Blake to care. "She had substance. She had something. The X factor," Farquhar suggests.

Whatever it was it was enough to catch the eye of his father Gerald. The two paintings and a print came from his brush, a late flowering in the work of the late artist, one that looked back to his days as a pop artist in the 1960s.

In and around Kinkell Castle the story of Laing's artistic career is on display in the shape of paintings and sculptures. In fact you could say that Kinkell Castle is part of that story. This, after all, is the castle Pop Art rebuilt.

Sitting between Dingwall and the Beauly Firth, and bearded by fields of barley, it is a muscular, puggish brute of a structure that dates to the turn of the 17th century but its current good health can be put down to Gerald Laing, who bought and restored it at the end of the 1960s.

Now might be the appropriate time for another kind of restoration. Or at the very least a reinstatement of an artistic reputation. In art historian Alastair Sooke's recent book Pop Art: A Colourful History, Laing only gets one passing mention. It's possible any future editions may require some adjustment.

It is five years since Gerald Laing died and suddenly the artist and the art are about to come back into focus. The Fine Art Society in London is hosting a major retrospective of his work, while next month the publisher Lund Humphries is to publish a catalogue raisonne of Laing's work.

At the same time a group show of British Pop Art, This Was Tomorrow, featuring the work of Laing alongside that of Peter Blake and Allen Jones, opens in October at the Kunstmuseum in Wolfsburg in Germany. Significantly, it is Laing's painting of Brigitte Bardot – that familiar face partially covered by a circle – that is on the posters and the sides of buses. In 2014 the original painting sold for more than £900,000 in auction. Laing is increasingly in credit in any accounting of British post-war art.

Since Laing's death Farquhar and his brother Sam have been trying to catalogue every single work their father created, "an enormous task," he admits.

"Over 500 individual works of art and then lots of prints and multiples and tapestries, as well as a considerable amount of writings. We haven’t counted up the number of drawings because there are so many. He was an incredibly prolific artist who managed to master several different disciplines. Drawing, painting, sculpture, tapestry, then getting into bronze casting, starting a bronze foundry, which ended up giving me my career indirectly, and then being able to rebuild castles, cars, motorcycles and write books about restoring this."

Laing's life story is equally supersized, a fat biography in waiting. It encompasses Sandhurst military academy in the 1950s, New York in the 1960s and the Highlands for the last 40 years of his life. Add in Andy Warhol and, as already established, Amy Winehouse, Pop Art, public sculptures, political paintings, three wives, five children, hot rod cars, motorcycles and possibly too much alcohol and you have a life fully lived.

"He achieved success twice in his life," Farquhar points out. "Once at the beginning of his career in New York in the 1960s and then in the last 10 years. But in the bit in the middle there were some scary times."

Farquhar and his wife and three young children live in Kinkell Castle. They have since 2012. It is a family home again, the thing his father always wanted it to be. "I grew up here, I got christened here, I got married here and now I live here," Farquhar points out.

"I'm glad my kids have a chance to have a go at the childhood I had. It was idyllic."

Life, like art, can be a matter of repeating patterns.

Gerald Laing was born in Newcastle in 1936 to a Scottish military father of whom he saw little and a mother who in his unpublished memoir Laing describes as "spoilt and also foolish". Their marriage was not a success. "His mother was not the warmest person," Farquhar suggests, "and he grew up yearning for some fatherly input."

Still, he followed in his father's footsteps and trained as an officer at Sandhurst. He ineffectually chased the IRA around the fields of Northern Ireland in the late 1950s before giving up the army in 1960 to go to London to study at St Martin's School of Art. Two years later he was married to his first wife Jennifer, was a first-time father to daughter Yseult and already on his way to being a name in the emerging Pop Art scene.

Pop Art was the 1960s in paint. Brash, loud, obsessed with celebrity and the white noise of the time. Laing responded to advertising, newsprint and film stills and began reproducing them in his bold, primary-coloured artworks, "painting reproductions of reality rather than reality itself," he once wrote, "so that the media image became the subject."

The 1960s were being born from the stained brown shadow of the 1950s. "Life was to be a Beach Party movie as soon as possible," Laing recalled. "It was quite a shallow approach; but it was very cheerful and positive, and it was precisely what the era demanded."

He once organised an event at the Slade School of Art – if it had happened a few years later it would have been called a happening – under the title Source and Stimulus – Space, Speed, Sex. The last three words are as precise a summary of the era and Laing's art at this time as any.

Pop Art was also a transatlantic affair. As early as 1963 Laing headed off to New York to meet his contemporaries in American Pop Art, from Robert Indiana to Andy Warhol, who at the time was still living with his mum. "I cannot remember having had any significant conversation with Andy when I met him, or indeed at any other time during the years which followed. It is very likely that there wasn't any."

Laing, though, was on the up and right at the heart of the new thing in art. And then at the end of the 1960s he decided to change everything. He left his wife and then left his New York life and decided to move to Scotland and find a castle to restore.

He married his second wife Galina Golikova, Farquhar's mother, the day before they sailed back to the UK on board the QE2. Farquhar was born in 1970 when his parents were already settled in Kinkell.

I wonder if the son knows why they settled here. "There's a story. My mother was doing work for an advertising agency and they were doing a campaign for Dove soap. The story goes that my mother was allowed to take this real dove home because it needed feeding or something. They put a map of Scotland on the kitchen table in their apartment in New York, put the dove on the map and said, 'Wherever the dove does its business, we'll go there.' It dumped all over the Black Isle, so …"

The castle was in a state when Gerald Laing bought it. The walls were still intact but the roof was partly missing and the upper floors were a mess. Then there was a later extension to the building that Laing decided to demolish. He managed to rebuild in about a year.

He brought the same self-discipline and drive to the restoration as he did to his work, clearly. Which does beg a question perhaps. What kind of father was he? "Not stern," Farquhar suggests. "Hands off, if anything."

Life for the son and the father revolved around fishing and hillwalking. "With my younger brothers he would invent catapults and bicycles that go on water and zip lines from trees. He would put his creative energies to very good use."

And all the while he was working. "Weekends didn't mean much to him. Christmas Day even," Farquhar recalls. "Food was fuel."

He shifted from Pop Art to bronze sculptures. In the kitchen where we sit talking a bronze portrait of Farquhar's mother looks over us. (Six months after Laing's death in 2011 a copy of it was stolen from Kelvingrove Museum in Glasgow. It was later returned.)

Bronze was now his medium. Laing even set up a bronze foundry in the garage. Farquhar would help out at weekends and on school holidays casting his own future. He now runs Black Isle Bronze near Nairn where he specialises in working with artists (he's just completed a huge casting for the artist Sandy Stoddart). "Eventually it turned into this fantastic business. We've got 16 to 18 people [working] now, doing projects all over the place."

The foundry also cast his father's work in his latter years. "I took that burden off him and he could just focus on making the sculpture. So we had a great, very close relationship. It was really special and probably quite rare. I was very fortunate."

His father worked hard and played hard, bringing the New York party life to the Black Isle. People visited. Artists, writers, cartoonists, the odd politician. "I remember once John Paul Getty arriving in a black helicopter and landing in the field, squashing all the barley," Farquhar says. "He stayed for dinner."

"My work has been varied, and so has my life – full of ups and downs; on top of the world one minute, descending into alcoholism the next," Laing himself once said. That's not quite how Farquhar remembers it. The 1970s were a boozy, blurry time but he can't remember alcohol affecting his father particularly adversely.

"It was a phase and then he stopped drinking and in the last years he didn't drink any hard stuff. When I was growing up there was more booze around and there was more of a party lifestyle. He smoked a lot as well. But that all stopped when he found himself with too much to do."

From the end of the 1970s Laing began to get commissioned for public works. They include The Wise and Foolish Virgins (1979), a frieze of bare-breasted women that can be seen on George Street in Edinburgh (look closely and you might notice that one of the virgins is modelled on Patti Smith on the cover of her album Radio Ethiopia). Then there was the Conan Doyle Memorial nearby in Picardy Place.

Bronze sculptures still dot the landscape around Kinkell Castle too. "That's wife number three," Farquhar points out as he shows us around.

Ah yes, family life for the Laings was complicated. Restoring Kinkell Castle was in some ways the artist's attempt to compensate for his own unhappy childhood. "My father's childhood went on to shape him," says Farquhar. "He wanted the identity of a family headquarters, a place where we could all get together."

And yet Laing struggled to find happiness within marriage. He divorced Galina and married Adaline Havemeyer Frelinghuysen in 1988. They had two sons together, Titus and Clovis. That must have had an impact on the rest of the family, you imagine.

"It was complicated," concedes Farquhar. "Certainly, women were attracted to him. That's for sure. He wasn't married towards the end and there were quite a few girlfriends who wanted to come up and see him when he was very ill. That was really awkward."

What was never in question was his love for the Highlands. His son can say the same. "I lived in London for three or four years then came back to the Highlands. This is the centre of the world."

Is that how your father saw it? "Oh yeah, definitely. He was quite pro-independence at one point. But then he wanted independence for the Highlands."

In his later years Gerald Laing returned to painting. His interest in pop culture was obvious in the Amy Winehouse paintings, though he also painted Kate Moss and Victoria Beckham. But this was also the man who made a painting about the Kennedy assassination soon after the event. He was always a political artist and, disgusted by the Iraq war and the revelations of torture at the Abu Ghraib detention centre near Baghdad, created angry work that condemned the then US president and the British prime minister.

"As an ex-soldier he was very angry about Iraq," says Farquhar, "and he particularly did not like Bush or Blair. He'd say to me, 'We used to be the goodies.' He grew up watching Spitfires and Messerschmitts flying over Newcastle."

Derek Bolshier, one of Laing's British Pop Art contemporaries, says there are constants in Laing's work for all the shifts in tone and medium. "Gerald, in the tradition of Pop Art, took from and was engaged with popular culture and politics. From the President Kennedy assassination to Amy Winehouse. He would surely now be engaged with Trumpism and Beyonceism."

He was never to get that chance. Gerald Laing died on November 23, 2011, at the age of 75. Still, all the anger and passion and energy lives on in his work. It's possible that if his reputation has suffered it's because his work was so mutable. He never stayed still. He was a shape-shifter in life and art. "We like to put people in boxes," his son says. "This exhibition is a Gerald Laing-shaped box."

How many sides does a Gerald Laing box have, Farquhar? "Well, there are 580 odd works, so start with that."

Gerald Laing 1936-2011: A Retrospective opens at The Fine Art Society in London on Monday. For more details visit thefineartsociety.com/ Gerald Laing: A Catalogue Raisonne, edited by David Knight, is published by Lund Humphries, priced £75, at the end of next month.