Children's author Jean Adamson, know for the Topsy and Tim series of books, has died aged 96, her family has confirmed.

In a statement released by publisher Ladybird Books, the family said they were announcing with "deep sorrow" that Adamson died on Sunday.

Adamson created the Topsy and Tim series, which follows the adventures of two twins and spawned more than 150 books, alongside her husband Gareth Adamson, who died in 1982.

Her family described her as a "devoted mother, grandmother, sister, author and great-grandmother, whose kindness and warmth touched the lives of all who knew her".

"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.

"Although we will take this time to mourn her loss, we will also ensure to celebrate her remarkable life."

Adamson was born in south-east London in 1928 and studied illustration at university.

She began working on children's books with her husband in the 1960s and in the 1970s created original animations for Yorkshire TV.

Francesca Dow, managing director of Penguin Random House Children's, which runs Ladybird, said Adamson's work was "uncharacteristic of the time" with her art style "being bright, pared back and uncluttered".

"Unusually for the time, Adamson gave Topsy an equal role to play in the adventures as Tim," Dow added.

The two characters first appeared in Topsy And Tim's Monday Book, originally published by Blackie in 1960.

It was unusual for ordinary children to be the lead characters in picture books, but the Adamson said they put youngsters at the centre of the narrative "because all the world is magic for children", and the choice of girl and boy twins was a way of ensuring gender equality.

The series has been in print for more than 60 years and has sold over 25 million copies around the world.

In 1984, the book series was adapted into a 60-episode animated TV show, and since 2013 three seasons of a live-action version have broadcast on CBeebies, winning the Bafta Pre-school Live Action award in 2016. The series still regularly airs on CBeebies.

Adamson's former agent, Mandy Little, said the twins 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".

Adamson was made an MBE for her services to children's literature in 1999, and in 2016 was made an honorary fellow of Goldsmiths College.