It all started the day the BBC put out the appeal for listeners’ recordings of old radio programmes that the Corporation, under pressure to save money, had deleted in the 80s.

But we don’t yet know when it will end.

They asked listeners to send in original CDs, cassettes, even reel-to-reel tapes and thousands did. Most of what was sent in was duplicate of what the BBC already had in its archives, a little was new and useful and filled a gap. Only one CD had been – lovingly? no, not lovingly, but very carefully – filled with an old old radio comedy programme. Previously thought lost and very valuable. Halfway, more or less, through the comedy show,  someone had added…. Something had been added. The Sound.

The Sound didn’t have a capital letter then: it was just a sound until you heard it, or met someone who had heard it. Then it had a capital letter and then sometimes, later, it was all capital letters because that’s how we who hadn’t heard it thought of it, thought of it sounding in someone else’s head.

And that’s how it all started. But we don’t yet know how it will end.