Barnes passed away on 4 August (15), but further details about his death were not released as WENN went to press.

He produced Bing Crosby's final six albums, and worked with Fred Astaire, Peggy Lee and Johnny Mercer during his 50-year career.

Barnes also wrote music books including Sinatra and the Great Song Stylists in 1974, The Crosby Years in 1980 and 1974's 20 Years of Pop.

Alongside his producing work, Barnes was a screenwriter who penned more than 90 scripts for the BBC. He wrote sketches for comedians including Peter Sellers and an Emmy-nominated TV documentary on Mercer called The Dream's On Me in 2009.

Barnes released a novel, The Sea Dogs, last year (14), launched a film restoration company and gave lectures on movies at universities.