LAWDY, lawdy, I do declare. My head is all Blanche DuBois, moving as slow as a streetcar when it comes to accepting change.

I’m set to take in a new staging of the Tennessee Williams classic A Streetcar Named Desire, but there’s a problem with the production - or rather a problem with my perception of the production.

Some of the key roles feature actors of colour. Stanley Kowalski (made famous by Brando in theatre and film) is to be played by actor Joseph Black, who is, well, black. Apartment block owner Eunice is played by Michelle Chantelle Hopewell, a lady who describes herself as ‘black-British’.

Now, this certainly isn’t an argument against featuring actors of colour. In recent years it’s been great to see Scotland’s changing diversity reflected in modern theatre.

But the stubborn brain can’t process the casting of actors of colour when it’s anachronistic. Kowalski was created in 1947 to be a Polish immigrant, and as such his race and class informed his status, his attitudes to life and women.

Tennessee Williams’ play is allegorical, a reflection on a layered, Deep South American society, a world of stark segregation in which a black man would not be allowed to live in an apartment block with a white woman, and certainly not a house owned by a woman of colour.

Similar issues with colour blind casting have emerged recently in touring productions such as The Railway Children. Although written at the turn of the century, one of the children in the cast was brown. It was unexplained, a given, as was the station master Mr Perk’s black wife.

In a 2017 production of Noel Coward’s Hay Fever, a comedy conceived to highlight and laugh at the social mores of English middle-class convention in the Twenties, one of the key characters was black. But the real-life probability being zero, appreciation of the play was diluted.

There are of course obvious reasons why actors of ethnicity are being cast in roles written originally for white actors. Emerging from drama college bubbling with talent and keen to forge their future, so many great (historical) theatre roles by the likes of Ibsen, Coward and Wilde are closed off. It’s understandable the theatre world should be all-encompassing. But this demands dramatic suspension of disbelief.

Some will argue theatre in itself is not a literal medium, a world in which tables and cloths can become sailing ships, a stage can be a planet in outer space. And theatre certainly allows for greater contrivance than television. But to many, the imagination can only leap from a platform of real probability.

It’s easy to accept rainbow casting in panto or indeed Shakespeare (which blends history and fantasy). And comedy theatre can be elastic enough to allow women, for example to play an approximation of a man. But I don’t want to see an approximation or heightened version of a man in dramatic theatre, such as when Kate Dickie starred in The Hard Man. I want to see a man play the role of a man.

The problem of verisimilitude is emerging more and more in modern theatre. Writer Edward Albee’s estate rejected at least one theatre producers’ proposals to stage a colour blind Who’se Afraid of Virginia Wolf? given it’s set in the early Sixties in New England in middle class academia. Yes, the story of the bickering couple could indeed feature two middle-class black actors, but it would have to be modernised - which makes for a different play.

The rights owners of Grease and Samuel Beckett plays have also rejected the idea of colour blind productions for the same logic.

The argument about truth has also appeared in television. Doctor Who writer Mark Gatiss, (an inclusive liberal) protested against the casting of a young “brilliant” black actor in the role of a Victorian soldier because “there weren’t any black soldiers in Victoria’s army”. Gatiss relented only after his own research revealed there was in fact one black soldier in the army at this time.

Film has also brought colour casting issues casting into the arena this week with accusations of “white washing” . Hollywood actor Ed Skrein pulled out of Hellboy, on discovering his character was of Japanese-American descent. Skrein was applauded for his decision and rightly so an argument both for helping ring-fence all-too-few ethnic roles and for truth.

But in discussing the Skrein story, Newsnight’s Emily Maitlis suggested colour no longer matters in acting, we should rainbow theatre, television and film. Yet, it’s not that simple for those who can’t ignore dialectic. And how do you instigate this strategy when the black acting community doesn’t speak as one voice; Samuel L. Jackson once argued against employing a black English actor as a black American.

Casting should be about the hiring best actor for the job, the person most likely to convince entirely in that role. But I don’t believe producers shouldn’t play with the playwright’s period inventions.

And sadly, my Blanche brain can’t see Stanley as anything but white. Nonetheless, I’ll go along to see Streetcar, in the hope colour vanishes, all prejudgement bleached away like the Southern belle’s dark roots.