‘Do black movies really not sell?’

The musical biopic is a staple of the Hollywood economy. Like an Airfix model kit it comes with the necessary parts presupplied: sex, drugs and a soundtrack. All the director need do is glue them together. Actors are keen too, as portraying musicians is like prospecting for Oscars: in recent years the lives of Edith Piaf, Ray Charles and Johnny Cash’s wife June Carter have all won statuettes for their stars. The life of Miles Davis, with its giant musical peaks and deep personal troughs, is tailor-made for the big screen. But for years he couldn’t be captured in a bottle.

It hasn’t been for want of trying on the part of Don Cheadle, who stars in, directed, produced and took a co-writing credit on Miles Ahead. Despite the support of Davis’s son, daughter, nephew and first wife Frances Taylor, the film was trapped in a pipeline for aeons. While he waited, Cheadle had plenty of time to turn himself into a trumpeter good enough to perform onstage in the film’s coda with Davis collaborators Herbie Hancock and Wayne Shorter (although it’s not him on the soundtrack). He proudly plays a clip of him on his phone, sobbing out a sliver of the solo from ‘Nefertiti’. ‘I never knew it was going to happen,’ he says, ‘but if it was going to happen I knew that I wanted to have that facility for sure. I didn’t want to be faking stuff.’

That was eight years ago. It has taken all that time to get to the point where he can sit cool and crosslegged on a sofa at a junket with the film in the can. The wait was so long that it easily outstrips Davis’s five-year fallow period in the 1970s when he stopped making music and concentrated on scoring drugs and dressing blingily.