By November 1964, Auger had acquired a Hammond organ for himself and recruited bassist Ricky Brown and drummer Micky Waller, both of whom were former members of Cyril Davies' All Stars. This more dynamic music secured the group work in clubs and discotheques, including the famous Flamingo Club in London.

In the summer of 1965 the Trinity were approached by Long John Baldry who had plans to put a "supergroup" together following the demise of the Hoochie Coochie Men. With the addition of vocalists Julie Driscoll and Rod Stewart (who had previously sung with the Soul Agents), plus guitarist Vic Briggs incorporated into the band, Steampacket was born. A hard-working r&b/soul band who were unable to make official recordings due to contractual reasons, Steampacket lasted barely a year before falling apart.

From the remnants of Steampacket Auger put a new version of the Trinity together in September 1966. Retaining the services of Driscoll and Briggs, Auger completed the line-up by adding a second guitarist in Gary Boyle and bringing in Roger Sutton (replaced by Dave Ambrose in 1967) on bass and Clive Thacker on drums. By now they were billed as Julie Driscoll, Brian Auger & The Trinity. The debut album "Open" was released in 1967 without attracting much attention until a cover of Bob Dylan's "This Wheel's On Fire" reached #5 in the charts during the early summer of '68. The success of the single rubbed off on the LP and belatedly pushed it into the album charts.

Two albums were released during 1968. The first was a purely instrumental album recorded without Driscoll, "Definitely What!", and the second "Streetnoise" which had Driscoll onboard. In 1969, Julie quit the group during an American tour and the Trinity struggled on for another year before folding in August 1970.