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If it weren't for deaf children, Wallace and Gromit may not exist.

How did I come to this unexpected conclusion? Answer: with a little help from Radio 4's Britain in a Box broadcast last Saturday and still available on ³ÉÈËÂÛ̳ iPlayer.

This series tells the stories behind the making of TV classics, and in the final episode Paul Jackson looks at , a ³ÉÈËÂÛ̳ children's programme that mixed art, animation, clowning, dangerous stunts and... sign language.

Running from 1964 to 1976, it featured fast-paced visuals and mayhem, not to mention explosions, and was based around creativity and art.

Each programme had a theme such as triangles, circles or black and white. There wasn't much talking in Vision On, but all words were signed by its main presenter Pat Keysell, a former teacher and deaf-theatre practitioner. It also featured inventor Wilf Lunn, Sylvester McCoy - who went on to be the seventh incarnation of Doctor Who in the mid-1980s - and Tony Hart.

You would be forgiven for not realising that the programme was, initially at least, intended for deaf children. Many young viewers didn't realise this, but it helped to normalise sign language in Britain and the many countries it was sold to around the world.

Those born after the mid-70s are unlikely to remember it, but will probably recognise the music from The Gallery segment and also the children's art programmes it spawned. Vision On begat Take Hart. Take Hart begat Hart Beat. Hart Beat begat Smart Hart, which begat On Your Marks and more. Tony Hart continued to present Vision On's offspring art programmes until 2000.

The animated clips and film sequences shown on Vision On such as The Prof and the Greeblies were contributed by amateur filmmakers. Amongst these were David Sproxton and Peter Lord. Towards the end of Vision On's run, they pitched a new character to the producers, a superhero called Aardman. Recognise the name?

Aardman Animations, as they became, then created Morph, the fractious little clay man who lived in a pencil box on Tony's table top in Take Hart. Later came Creature Comforts, Peter Gabriel's Sledgehammer video, the feature film Chicken Run, and, of course, the much loved Wallace and Gromit.

• Listen to Britain in a Box for more behind the story of the memorable long-running children's programme and to find out what television offered deaf people before Vision On.