The band was established in 1966, initially featuring two lead vocalists: Keith (Budgie) Radford and Brian Johnson. Shortly thereafter, Keith departed, leading the group to adopt a four-piece lineup that, despite various personnel changes across all instruments, would remain consistent, with the exception of a brief three-month period in 1973 when the band expanded to five members. Throughout these transitions, it was Brian's vocals that provided a continuous thread for the band. The lineup included John Brown on bass, Trevor Mee on lead guitar, and Kenny Rickard (unrelated to Steve) on drums as Pebbles performed in local venues across the Upminster and Romford areas.

By 1967, the band was regularly appearing on the university circuit alongside acts such as Wainwright's Gentlemen (later known as Sweet) and The Brian Auger Trinity. In 1968, guitarist Adrian Baker took over the lead guitar position, and Pebbles recorded two singles for EMI: "Peter The Painter Man" and "C'mon Marianne." They also covered "The Proud One" well before the Osmonds achieved chart success with it in the 1970s. Pebbles maintained a busy touring schedule, sharing stages with artists like Dave Dee, Dozy Beaky Mick & Tich, and The Flirtations. With Adrian's keen sense for harmonies and his formal musical background, the band developed a notably tight vocal sound.

In 1969, Roy Morgan joined on drums, becoming a pivotal force both on stage and in management. He quickly arranged for the Barry Collings agency to represent the band, which led to extensive touring across the UK, establishing Pebbles as Britain's leading vocal harmony group. The band gained regular spots on Radio 1 and Radio 2, contributing live recordings for their programming. They released three singles, all written by the prolific songwriting duo Ken Howard and Alan Blaikley. The first single, "Stand Up and Be Counted," achieved chart success in Australia and New Zealand, but its follow-ups, "Goodnight Ma (Don't Turn the Light On)" and "First Time Loving," did not gain similar traction in the UK, despite receiving considerable airplay on Radio Luxembourg and the pirate station Radio Caroline.

By the end of 1971, the musical landscape had shifted significantly from when Pebbles first emerged, marking the onset of the glam rock era and necessitating a change in the band's style. This transformation occurred when Brian and Roy collaborated with Joe Ryan and Martin Kemp from Finian's Rainbow. Although the band retained the name Pebbles, their sound evolved into a more punchy style. In the summer of 1972, Brian and Martin, performing under the name Mark & John, provided vocals for a Howard/Blaikley composition titled "This One's For You." This track was recorded at Advision Studios in London with a 53-piece orchestra and released on Jonathan King's UK label. Despite receiving extensive airplay on Radio North Sea International, a notable pirate station, the single did not chart in the UK, and no follow-up materialized.

Pebbles continued to tour and record BBC sessions, but they struggled to secure a recording contract during this period. After a two-week club engagement in Switzerland, the band welcomed another change in personnel. Kenny Rickard temporarily filled in on drums until Clive Jury arrived from Cornwall. However, this lineup was short-lived, and local drummer Steve Rickard soon took over. Over the following year, the band spent three months working the Wheatley Taverns circuit in London, eventually recruiting Chris Weakes on keyboards and settling into a residency at Crackers nightclub in the West End.