Colour-blind casting. It’s a phrase that’s used to mean that the ethnicity of the cast performer isn’t taken into account when casting a role. And in practical terms, that tends to mean that a role traditionally played by a white actor is being played by a non-white one.
In ‘straight’ theatre, it’s almost taken as given these days – despite the same examples being trotted out time after time (David Oyelowo’s Henry VI for the RSC, forever cited whenever the topic arises, was 11 years ago in 2000, for goodness’ sake).
But in West End musical theatre, there do seem to be precious few examples.