Kenneth Williams as the voice of methane? It's a gas! This British Gas sponsored short is the origin of cult kids TV classic Willo the Wisp

Remember Willo the Wisp? Commissioned to make a film about the discovery and use of offshore natural gas, the ever inventive Nick Spargo decided to make methane itself into a character and called on unique voice talent of Kenneth Williams to bring it to life. First appearing as the phenomenon of will-o'-the-wisp, then voicing the gas on its path from the seabed to the home this short is an unexpected delight.

The character clearly had more life in it, so it was perhaps unsurprising that it returned in a 26-part series first shown on the BBC in 1981 and then much repeated. Nick Spargo started his career in cartoons at the Gaumont-British Animation studio which was set up after WWII by J. Arthur Rank, which set him up for a long career in the industry with particular skills as a writer.