Peel's show was an outlet for the music of the UK underground scene. He played classic blues, folk music and psychedelic rock, with an emphasis on the new music emerging from Los Angeles and San Francisco. As important as the musical content of the programme was the personal – sometimes confessional – tone of Peel's presentation, and the listener participation it engendered. Underground events he had attended during his periods of shore leave, like the UFO Club and "The 14 Hour Technicolor Dream", together with causes célèbres like the drug "busts" of the Rolling Stones and John "Hoppy" Hopkins, were discussed between records. All this was far removed from Radio London's daytime format. Listeners sent Peel letters, poems, and records from their own collections, so that the programme became a vehicle for two-way communication; by the final week of Radio London he was receiving far more mail than any other DJ on the station.