He also claimed the credit for the Byrds’ distinctive sound, saying he and producer Terry Melcher came up with it after the group’s initial recordings were underwhelming. “It was our interaction,” he said earlier this year. “Terry didn’t know what was missing. It was a long time ago, but the key to it all was the guitar solo I had done on Melcher’s Summer Means Fun single, recorded under the name of Bruce & Terry. We put so much reverb on it that it brought the guitar to life. I mentioned to him that that was my favorite solo. We listened to it again, and that’s how we arrived at the conclusion that what we needed was that triple reverb.” (Among other claims: he suggested the sitar on Paint It Black ; Elvis sang through his body when he lost his voice before a club show; and he met James Dean – three years after his death. Sloan may not have been a wholly reliable witness.)

But Sloan was a musician, too – he was part of the elite group of LA session players known as the Wrecking Crew – and in 1965 he and Barri formed their own group, the Grass Roots. It was, at least in part, a cynical group – Adler, too, had noticed that folk rock was quite the thing and wanted a group playing it on the Dunhill label. But Sloan and Barri weren’t really looking to be in a band, and having formed it they promptly set about recruiting musicians to take their places (one lineup of the Grass Roots would include Creed Bratton, later to play Creed in the US version of The Office). But the songs he wrote for them were terrific, too – Where Were You When I Needed You could have been a standout on any of the first three Byrds albums. Bear in mind, too, that at the same time as doing this he was able to turn out conventional chart pop such as Secret Agent Man for Johnny Rivers. He was nothing if not versatile.

Then, in the late 60s, Sloan pretty much disappeared – aside from a poorly received solo album in 1972, he was silent until the 90s, hence Webb wondering in song what had happened. He claimed to have been fleeing threats from Dunhill after leaving the label. He fell into drug use. At one point, Brian Wilson’s since-discredited therapist Eugene Landy claimed that he had been Sloan all along.

He returned last decade, a largely forgotten figure trying to claim his dues. But the songs he wrote never died. “I think you know when you’ve written a hit song – I can’t tell you why that is, it’s almost like when a mechanic finds the problem with a carburettor and then the carburettor kicks into action and you kind of know … there’s just a feeling of joy and release, that you’ve done something wonderful,” he said last year. “It thrills you, and you get the feeling that if it thrills you, it will thrill other people as well. And when you hear that in other people’s work … you know that other people have been thrilled by it.”