Jean Adamson, creator of the beloved Topsy and Tim children’s novels has died aged 96, her publisher has confirmed.

The writer and illustrator, who died on Sunday, was responsible for more than 150 titles featuring twins Topsy and Tim, which she began with her husband Gareth Adamson.

“Jean was a devoted mother, grandmother, sister, author and great-grandmother whose kindness and warmth touched the lives of all who knew her,” her family said in a statement. “Her presence will be greatly missed, but her memory will live on in the hearts of her family and all those she loved or that remember her through her stories.”

Mandy Little, Adamson’s literary agent, described working with Adamson as “a rare privilege”.

“She never lost interest in the two little black-haired twins as they explored what the world had to offer over decades, making sure always that Topsy got as much of the action as Tim. They were close to her heart for, as she once told me, they were based on herself and her beloved brother Derek, who were inseparable as children,” Little said.

“Meetings at her house were always very relaxed and her sense of what was important in life meant that they could be fun as well as businesslike,” she added. “And Daphne the greyhound usually sat in the biggest chair.”

Born in Peckham in London in 1928, Jean studied illustration at Goldsmiths College, where she met Gareth. She later taught at Goldsmiths, alongside her work as a freelance artist and illustrator. She married Gareth in 1957, and the couple moved to Newcastle, where they began working on the Topsy and Tim books, with Jean researching the story and illustrating, and Gareth writing the stories.

The first book in the series to be published was Topsy and Tim’s Monday Book in 1960, and more than 150 titles followed. After Gareth died of a brain tumour in 1982, aged 56, Adamson carried on writing the books alone.

“I pretty much wrote non-stop for 20 years. We needed the money,” she told the Express in 2013. “His death was absolutely tragic. It was nice to have Topsy and Tim though. I could carry on something we had started together.” To Adamson, the characters were “like part of the family”.

The Topsy and Tim titles have sold more than 25m copies around the world, with 1.9m copies sold in the UK alone since 1998. The stories have been adapted for screen, first as animations created by Adamson and her husband, appearing on Yorkshire TV in the 1970s, and again as a live action series in 1984. A second animated TV series arrived on screens in 2013, which still regularly airs on CBeebies.

Adamson accepted an MBE for her services to children’s literature in 2000 and in 2016 was made an honorary fellow of Goldsmiths.

Francesca Dow, managing director of Penguin Random House Children’s, said: “Jean and her husband Gareth’s work was uncharacteristic of the time, with Jean’s art style being bright, pared back and uncluttered. They made sure that the depictions of these first experiences were well-researched so that parents and children could trust them. And, unusually for the time, gave Topsy an equal role to play in the adventures as Tim.”

“Jean will be greatly missed,” Dow added. “She leaves behind a gift to children and their families in her greatest creations.”