The Ruling Class, his most famous work, helped Peter O'Toole to an Oscar nomination in 1972 when it was turned into a film.
Apparently Barnes completed several projects that are now waiting to be made.
"The playwright became a celebrated older dad when his wife Christie gave birth to daughter Leela when he was aged 69, then within a few years to triplets Nathaniel, Zachary and Abigail.
This became the inspiration for one of his last completed screenplays, Babies, which is expected to be a two-part drama for Granada and tells the story of a man who become the father of triplets late in life.
Barnes had also just completed three other high-profile projects.
The screenplay for the film From The Moon To The Stars is due to be directed by John Irvin, who directed the Boys from County Clare starring Andrea Corr of Irish band The Corrs.
He had also completed Easy Virtue, an adaptation of a Noel Coward play, and Sea Change, which will feature and be produced by Kristin Scott Thomas, the female star of the movie The English Patient."