This boss near-instrumental from 1967 simply attributed to “The Paris Studio Group” features a mean harpsichord – something right out of Lurch from The Addams Family:

As NME informs us:  “Main title theme as used on Tony Hart`s UK TV series, Vision On – a children`s TV series aimed at deaf children which ran from 1964 to 1977. The music is composed & performed by Claude Vasori, better known as Caravelli.”