In the gloriously dated tones of early Sixties BBC radio, the announcer declares: "Now we have a completely different sound, that of the five young gentlemen who are making such an impact on the hit parade at the moment."
The five young gents are The Rolling Stones and these 1960s BBC sessions are the most eagerly awaited rock music archives, certain to sell in huge quantities when they are eventually released.
Even Jagger, Richards and the rest of the band, currently on a world tour, have not heard them since they played the sessions on the Light Programme and World Service between 1963 and 1965.
With BBC sessions by The Beatles and Led Zeppelin already released by BBC Worldwide to huge acclaim, it is now hoped that The Stones material will be released later this year.
Having listened to 20 tracks and assorted interviews, I can reveal that the results are fascinating, raw, earthy blues and rock'n'roll, with moments of surprising tenderness.
There is also one memorable interview with Keith Richards, his voice slurred, talking about "my quest for the holy grail, that cup of blood". Then, asked about parental fears about daughters going out with members of the group, he replies, again slurring: "I've `ad a lot of trouble with mothers." It wouldn't get on the air now, muttered the stunned BBC executive next to me.
And so to the music, introduced in many cases by the late blues musician Alexis Korner on his radio show. He pays tribute to "Mick Jagger vocalising there with the skillful guitar work of Brian Jones and Keith Richards".
From Saturday Club in 1965 they sing "Satisfaction". "It only took us two hours to actually record it," Mick reveals. "That included arranging it `cos not everybody knew the song." He begins singing almost in a falsetto, with Charlie Watts giving a constant rhythm with a repeated three strikes of the cymbals, quite different from the released version.
Most interest will focus on the unreleased tracks. The best of these is "Cops and Robbers", formerly performed by Bo Diddley. It is virtually a talking blues. Jagger, with a thick American accent duels with Jones' harmonica snarling: "We're going to put him so far back in gaol, they're going to have to pump air into him."
Then there are two Chuck Berry standards: "Roll Over Beethoven", a much rawer version than The Beatles' cover of the song, with Jagger making a rare ad-lib and perhaps anticipating his androgynous phase. Instead of "Don't you step on my blue suede shoes" he sings "Won't you step on my high heel boots?".
In Berry's "Memphis Tennessee" there is a surprisingly tender Jagger vocal in front of Richards' finger picking guitar. Oddly though Jagger sounds very English here. "Just a half a mile from the Mississippi bridge" is enunciated as plummily as if he is reminiscing about childhood in Dartford.
The fourth unreleased track, "Fanny Mae", again has the late Brian Jones' swooping harmonica at its core.
Snatches of this music were heard in the Eighties on a Radio One programme on the Stones. But much has never been heard for over 30 years. "It is astonishing," said John Willan, head of music at BBC Worldwide, "that no one has thought to release this before. It is outstanding - raw, unsophisticated and compelling."