This from 'Jimmy Page: Magus, Musician, Man' by George Case:
Around the same time Page was producing him in the studio, Clapton visited his house in Epson to have some private jams, which Page also recorded. "The Bluesbreakers were playing over in Putney and Eric came to stay at my house. I had a Simon tape recorder that you could DI into [directly inject electric instruments without first playing through an amp], so the two guitars went into the machine and I just did these tapes of Eric and myself playing." The DI trick enabled a huge amount of distortion while the two musicians played around with different twelve-bar I-IV-V progressions. But Page let Andrew Oldham's Immediate label know about the tapes ("I was really championing Eric, as you would"), and they were confiscated as part of both Page's and Clapton's contractual obligations. "I argued that they couldn't put them out, because they were just variations of blues structures, and in the end we dubbed some other instruments over some of them and they came out, with liner notes attributed to me... though I didn't have anything to do with writing them. I didn't get a penny out of it, anyway." This rather exploitative move on the label's part-they were released when given rhythm tracks by Rolling Stones Charlie Watts, Bill Wyman and Mick Jagger playing harmonica-led to some mistrust of Clapton toward Page, and Page's own frustrations at not owning music he had made. It was a bitter lesson.