"I am now more often working behind the scenes, behind the camera as a producer and a writer, and just like those bad old days in the 1970s in front of the camera, I am still all too often the only black person in the room," Lenny Henry recently said as he called for tax breaks to help persuade the British film and television industry to improve diversity.

When I saw the picture of Henry standing outside No. 10 Downing Street with Meera Syal and others, I admit I breathed a heavy sigh and experienced a familiar sinking feeling, a feeling that I had seen it all before. In 2014, Henry threatened a boycott of the licence fee over the lack of diversity – and not much happened, except that the BBC commissioned Danny & the Human Zoo, written by and starring Henry, and directed by Destiny Ekaragha, still among only a handful of Black British women to direct a feature film.