The Moody Blues star Ray Thomas has died at the age of 76. The flautist and vocalist died suddenly on Thursday, his record label said.

Cherry Red Records and Esoteric Recordings said in a statement: “We are deeply shocked by his passing and will miss his warmth, humour and kindness. It was a privilege to have known and worked with him and our thoughts are with his family and his wife, Lee, at this sad time.”

In 2014 Thomas revealed on his website that he had been diagnosed with prostate cancer. He said he had received his diagnosis in 2013.

“My cancer was inoperable but I have a fantastic doctor who immediately started me on a new treatment that has had 90% success rate,” he wrote. “The cancer is being held in remission but I’ll be receiving this treatment for the rest of my life.”

Born in Stourport-on-Severn on 29 December 1941, Thomas started out in blues and soul groups in the 1960s and later formed the Moody Blues alongside Mike Pinder, Denny Laine, Graeme Edge and Clint Warwick.

Although the band’s roots lay in the blues, their 1964 hit Go Now was a foretaste of the lush, orchestral sound that came to be called progressive rock.

Their 1967 album Days of Future Passed is a prog-rock landmark, and Thomas’s flute solo on the single Nights in White Satin one of its defining moments.

Thomas wrote several songs for the band, including the trippy Legend of a Mind and Veteran Cosmic Rocker.

Thomas also enjoyed solo success with the albums From Mighty Oaks and Hopes Wishes & Dreams. The Moody Blues, including Thomas, were to be inducted into the Rock & Roll Hall of Fame in 2018.