For seven years, Ms Griffiths has been director of the National Literacy Association. Prior to that, she worked for the British Dyslexia Association. Now she is giving up her day job to become Charlie Rose, lyricist and singer for State of Undress, a category-defying duo, with one album and a string of performances under her belt.

“Very few people at the NLA know about this other life,” the mother-of-two said. “I thought it might not be done for the director to be strutting her stuff. My colleagues were quite shocked when I told them why I was leaving.”

Ms Griffiths, 44, and her melody-writing husband, Alan Rose, began to perform two years ago, after a musical hiatus of four years. They decided their band might be more than a part-time hobby after a sell-out concert at a local arts centre.

“Call it a mid-life crisis, but we didn’t want to be there in our dotage thinking, if only we’d done this,” she said. She cites her musical influences as U2 and the Hothouse Flowers, which come together when she writes songs with “very adult themes”. These include commercial whaling, an old woman contemplating death, and a husband who insists that he is technically faithful to his wife, despite numerous infidelities.

Their most recent song is based on Follow Me Down, a children’s novel by Julie Hearn, set in an 18th-century freak show. If children like the song, Ms Griffiths says, it may encourage them to read the book. In this way, she believes, her new job is surprisingly similar to the old.

“Whenever the NLA talks about ways into literacy, we always include song lyrics and rap. It’s a way of self-expression, without worrying about grammar or spelling. So we’d like to work with children more.

“But we’re not the sort of band you usually see on Top of the Pops. Yes, in my wildest dreams, a Number One record would be lovely. For now we just hope to be booked for a couple of concerts.”