The three teenagers and school friends John Simms (guitar, vocals), Mark Sheather (bass) and Ken White (drums) from the London borough of Acton had been playing together as a college blues-rock band since the late 1960s. These young and rather talented musicians quickly built up a fan base in the college scene and in clubs as a cover band. With their first original songs, they even won a talent contest at London’s Marquee Club. This impressed manager Ashley Kozak, who secured them a record deal with Vertigo, the progressive sub-label of Philips. The power trio, with an average age of 18 (John Simms was even younger), renamed themselves Clear Blue Sky.

In 1970, they recorded their self-titled debut album at Island Studios under the guidance of producer and Nirvana musician Patrick Campbell-Lyons. It was released in January 1971 and features one of the very first cover designs by the artist Roger Dean. With an unusually mature approach, the three young musicians, full of vitality, presented their blend of hard blues rock, progressive hard rock and heavy psych, which at the time could easily stand up to comparisons with Led Zeppelin. They are now even regarded as one of the pioneers of heavy metal. However, as with most Vertigo acts of that era, virtually nothing was spent or done in the way of promotion or advertising. Consequently, the band disbanded shortly afterwards, disillusioned. The original English vinyl on the legendary Swirl label is a coveted collector's item worldwide.