Guitarist, singer and songwriter John Richard “Jackie” Lomax, has passed away at the age of 69. Lomax is best known for his single “Sour Milk Sea,” which was written by George Harrison, recorded by Lomax, Harrison, Paul McCartney, Ringo Starr, Eric Clapton and Nicky Hopkins for release as a single on The Beatles’ label Apple Records in 1968.

Lomax first came to prominence playing bass and singing with Beatles contemporaries The Undertakers. Following that groups dissolution, Lomax started his own The Lomax Alliance, and was picked up by The Beatles’ manager Brian Epstein who hooked The Lomax Alliance up with CBS records for a deal that resulted in two singles for the band, plus one additional single listing Jackie Lomax as a solo artist.

Following Epstein’s passing, Lomax moved to Apple Records, and secured George Harrison as the producer for his debut solo album, Is This What You Want? Despite the presence of members of The Beatles, Clapton and legendary studio musicians from the Wrecking Crew, the album only reached number 145 on the US Billboard 200 chart. Lomax continued to release solo albums through the mid-70s, but continued to suffer from poor sales. He also kept busy playing in an assortment of smaller bands that featuring supporting members of higher-profile groups such as Yes, the Rolling Stones and King Crimson.

Is This What You Want? was remastered in 2010, with the addition of a number of bonus tracks including alternate mixes and outtakes from the original sessions. Lomax was reportedly in England to attend the wedding of one of his children at the time of his death.