Bod was a Buddhist, the Clangers went on a mission to undermine Ted Heath’s Government and Bagpuss was a political comment on industrial relations. The subversive secrets behind children’s shows from the 1970s can now be revealed.

Mothers relied on “children’s hour” as a controversy-free zone to keep their young families occupied but the creators of the era’s classics had a bigger idea – to politicise a new generation.

A BBC Four series, Children’s TV on Trial, has discovered that Bod, Mr Benn, The Tomorrow People and Bagpuss all served to undermine traditional values of respect for authority during a volatile decade.

“I was in a right state of discontent in the 70s about Heath and the miners and the three-day week,” said Oliver Postgate, co-creator of Bagpuss and the Clangers, pink woolly creatures that communicated through whistling sounds.

“The Government was being subverted by politics so I said, ‘Can I make a Clangers special about the folly of politics?’ ” The result, Vote for Froglet, was shown during Harold Wilson’s successful election campaign of 1974 but was swiftly withdrawn and has not been broadcast since. A rescued clip shows a didactic Clanger arguing: “Party politics is just a question of power. Are you listening to me?” and proposing a government of the Soup Dragons.

Postgate introduced industrial unrest into Bagpuss, with an episode in which the mice go on strike, chanting, “Mice not sing, mice not work. Mice strike!” He said: “This was just part of my inconvenient political concerns at the time.”

Bod, the animated BBC series created in 1975, was really a primer in Eastern philosophy. The animator Alan Rogers said: “Michael Cole, the creator, always wanted to put a message across. He had a Zen take and wanted to put across a Buddhist story. In one story the cherry blossom leaves fall but soon they are green again. It says ‘always be optimistic about life’. ”

Richard Carpenter, writer of The Tomorrow People, said: “Television is the world’s biggest toy so you may as well impose some of your prejudices on it.” The series followed a group of children who represented the “Homo superior”, the next stage of evolution. Carpenter said: “I was saying to kids, ‘All big government must be bad – authority is not infallible.’ ” He cast black children as “superiors” in the face of opposition from advertisers. The politics escaped Lewis Rudd, former head of Thames children’s programmes. He said: “If we thought it was trying to bring down society we would not have wanted to do it.”

Mr Benn, in which visits to a fancy dress shop prompted an adventure, was grounded in the tradition of social realism. David McKee, series creator, said: “I was annoyed when an adventure ended up just being a dream. I wanted Mr Benn to be a real adventure – that’s why he always brings a souvenir back. I wanted him to be a Mr Everybody, not too rich or poor, living on an ordinary road that anyone could associate with.”

Children’s TV on Trial is shown tomorrow at 9pm, then nightly until May 31.

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