A collection of Ivor the Engine episodes which have not been seen since the 1960s have been unearthed in Kent.
The 24 reels were found at the back of the converted pigshed in Blean, Kent, where Peter Firmin and Oliver Postgate created their much-loved films.
Postgate, who died in 2008, and Firmin were also behind other favourites including Bagpuss and The Clangers.
Postgate's son, Dan, said the episodes could be released once they had been converted into a digital format.
He said the black and white episodes were discovered by an agency that was digitising his father's old films.
Mr Postgate added: "My dad stored some of the old 16mm film in cans in an outbuilding on Peter Firmin's farm. They were stacked at the back of the shed in a store area.
"Kaleidoscope took away the cans and reported back that there were a lot of old black and white Ivor the Engine episodes.
"They haven't been seen since 1969. Most were remade in colour later but these are the raw originals."
He said: "They will be of interest to a certain number of people as they have a particular wistful quality to them."
The last full length story of the Welsh engine and his driver, Jones The Steam, was made in 1977.
The cartoon and its tales of Dai Station and Idris the Dragon first appeared on television in 1959 and was then revamped in the mid-1970s.
Ivor reappeared on Welsh TV screens in 2004 to promote the former BBC Wales digital channel 2W.
In December 2009 Mr Postgate announced that he planned to write a new Ivor the Engine story to raise money for charity.