Elena Lazzarini, a researcher from Pisa University, believes the enormous fresco is replete with homosexual imagery, including a man being dragged into Damnation by his testicles and kisses and embraces between male figures.

She has explored the theory in a new book, claiming that Michelangelo drew much of his knowledge of male anatomy from his frequent visits to gay brothels and 'Turkish baths' in 16th century Italy.

"The virile male bodies are inspired by the physiology of labourers engaged in physical exertion, with taut muscles, strenuous exertion and pain etched into the expression on their faces," said Miss Lazzarini....