In the posthumously-published book 'The Kenneth Williams Diaries', Williams professed to a dislike for the show, considering it too slow-paced and technically indifferent to capture children's imaginations. The runaway success of the series, combined with the cult following it acquired among adults, consequently proved him wrong.
The character Willo the Wisp, as voiced by Kenneth Williams, originally appeared in 1975 in a short animation called "Super Natural Gas" for British Gas. This animation is included in the 2005 DVD release of the series. The character first appeared in the Doyley Woods setting for the 1981 TV series.
The Willo The Wisp character, voiced by Kenneth Williams, was created by Nick Spargo for an animated short film called "Supernatural Gas" in 1975. Spargo wanted to develop the character further, and, in September 1981, the "Willo The Wisp" TV series made its debut on BBC 1 in the UK. This established the setting of Doyley Woods, and the other characters - Mavis Cruet the fairy, Carwash the cat, Evil Edna - the witch who was also a television set, and so on. The series was revived in 2005.