Children's author behind the Meg and Mog series who also founded a successful audiobooks company
Helen Nicoll, who has died aged 74, was best known as the writer of the Meg and Mog books for children. When we first decided to create a picture book about a witch and her cat, in the early 1970s, my condition as the illustrator was that if the witch were to make a spell, it must never work – and that is how the series began. Helen and I were taken on by the editor Judith Elliott at Heinemann who immediately asked for two books instead of one. The books are now in their fifth decade.
Helen's style in everything she did was to be clear, brief and to the point. She wanted things to be right – for instance, when we worked on the book Meg's Castle, I drove her on a research tour of Welsh castles, in appalling weather, and she came up with perhaps my favourite spell: "Double trouble/ Rock and rubble/ Oil boil/ Cauldron bubble." Needless to say, the spell didn't work – as we had agreed.
At the time, Helen lived near Marlborough in Wiltshire, while I live in Barnes, south-west London, so we had to develop a way of working together. We hit on the idea of meeting at the Membury service station on the M4 motorway. This became our routine. We were regulars, the friendly staff didn't seem to mind and I always brought a little bunch of flowers to put on our table. We spent many frenzied hours struggling with stories and pictures accompanied by any number of cups of tea. Helen was an inspiring but merciless collaborator and usually managed to get her way with her innate charm.
We polished up the end result on the telephone and in our editor's office. We produced around 20 Meg and Mog books – including Meg on the Moon, Meg's Eggs and Mog's Missing – which on the whole are all still in print from Puffin Books.
In 1981, Meg and Mog made their entrance on the West End stage, in an adaptation by David Wood at the Arts theatre with Maureen Lipman as a brilliant Meg. Soon, Helen had hit on the idea of producing audio versions of the books with Maureen as an inspired narrator and a magician from the BBC Radiophonic Workshop handling the sound effects. In 2003 our characters were animated for television, with Meg voiced by Kay Ripley, Mog by Phil Cornwell and Owl by Alan Bennett.
Helen was born and brought up in Westmorland (now Cumbria). She was educated at Badminton school, Bristol, and worked as a teacher. When we first met in the 1960s, she had just been offered a job with BBC Television to develop a new children's programme which she named Watch! She needed an artist and I was the lucky one she chose.
The BBC job was hard work but inspiring. We developed the idea of drawings appearing on the screen as if by magic so the artist was never seen. The secret was that I drew my strong black on white pictures on the back of a glass screen. In order to be invisible to the camera I had to wear black from head to foot, with a black veil in front of my face. I was allergic to something and kept on having to blow my nose through the veil, which had to be changed at regular intervals.
As the programme seemed to be a success, Helen suggested that we should make up stories for this new medium that we had invented. These stories taught us how to create an illustrated narrative and, when Helen left the BBC in 1971, we decided to have a go at creating picture books together. We never looked back.
Helen had a house in the west of Ireland where we had a writing spree and she also loved the Lake District, where I went to see her several times to work on our later books. We had long walks over the hills, sometimes in perpetual drizzle which didn't seem to matter at all. I remember my dog chasing her neighbour's sheep into a corner and Helen keeping astonishingly calm about the whole matter. On one occasion we started work at her parents' house in the gracious drawing room and then ended up sitting all day huddled in the only warm corner of the kitchen to complete our work next to the Aga.
In the 1980s, Helen became the editor of the Junior Puffin Club magazine, which we called The Egg! I did a poster with some little puffins on a train stopped at a station. The great Puffin publisher Kaye Webb added an unforgettable caption: "Your ticket to READING."
Helen's great interest became high-class audiobooks – classic novels read by great actors. She had the knack of finding the right voice for the right book. She founded the company Cover to Cover for which I did some graphic design: rather than being paid for the job, I asked for copies of the audio books. I have listened to many of the titles repeatedly and the voices have become old friends. Helen's professionalism and success in this field included being taken up by JK Rowling who gave her the rights for the Harry Potter books.
Helen is survived by her husband, the interior designer Robert Kime, whom she married in 1970, and their children, Hannah and Tom.
• Helen Morag Nicoll, author, born 10 October 1937; died 30 September 2012