In 1978 the British Broadcasting Corporation introduced an archival policy. Prior to that, they practiced “wiping” -- where recordings were either erased for re-use or destroyed.
Nineteen-seventy-eight was the same year in which the leader of Britain’s Conservative Party, Margaret Thatcher, told Gordon Burns on Granada TV that “people are really rather afraid that this country might be swamped by people with a different culture.”
The following year, upon taking possession of 10 Downing Street, Thatcher paraphrased St. Francis of Assisi: Where there is discord, may we bring harmony. Where there is error, may we bring truth. Where there is doubt, may we bring faith. And where there is despair, may we bring hope.”
I only found out about the BBC’s wiping policy while looking for episodes of The Bed-Sit Girl (1965), whose template appears to have been glamorized by the American Broadcasting Corporation’s That Girl (1966-1971). Apparently all twelve episodes of The Bed-Sit Girl had been wiped.