In the 1920s, a group of Chinese students protested to parliament about no less than six concurrently running plays in London’s West End starring white actors in yellowface, which the students believed portrayed Chinese people in a derogatory way.

A decade later, on the set of a silent film shot in London, one group of Chinese immigrants came to blows with another over their appearance as background artists in films starring white actors in yellowface. Around the same time, the lone Chinese-American screen star of the era, Anna May Wong, was growing increasingly disenchanted with an industry that, despite her appearances in films such as The Toll of the Sea and Piccadilly, was reluctant to give her leading roles.

The truth of the matter is that conversation and protest about the treatment and portrayal of east Asians on UK stages and screens has been going on for a long time now. As a result of these protests, in recent years artists of east Asian descent have made enormous strides in British theatre, in a series of powerful productions that have sold well to audiences of all backgrounds, who have received them warmly.

But on UK screens, we are still subject to piecemeal representation mired in tokenism. Ongoing monitoring research commissioned by Equity’s Minority Ethnic Members Committee is starkly revealing, even in its preliminary findings. It says that unless British east Asian actors are portraying “foreigners”, they are simply not on screen.

When I read articles by renowned UK casting directors (nearly all white) who have unearthed the major stars of our industry, in which they speak about what they look for in an actor, I often wonder what the answer would be if they were asked what they look for in an east Asian actor.

Because, come on, the answer is surely that an east Asian actor should look and sound as much like Jackie Chan as possible. The fact is that British TV, renowned the world over for its classy and tasteful production values, is back in the age of Mr Wu when it comes to people of east Asian heritage. It surely should be an embarrassment.

Take Channel 4’s Chimerica, for example. The show came with a great pedigree, based as it was on Lucy Kirkwood’s award-winning stage play. It also relegated a real-life Chinese tragedy – the 1989 Tiananmen massacre, which the Chinese Communist Party have tried to erase from history – to the geopolitical backdrop to the main plot about a (fictional) white US photojournalist who supposedly took the iconic shot of the anonymous “tank man” whose fate is still, to this day, unknown. The show was even cited by one of its east Asian cast as the UK’s “Crazy Rich Asians moment”.

Hardly. Crazy Rich Asians, for all its problematic reduction of “Asians” to a single racial and socio-economic group, did at least foreground actors of east Asian descent playing rounded, fully-formed characters in their own narrative and acting in their own first language: English.

Chimerica – and it’s only the most recent example – featured copious amounts of what the academic Daphne Lei describes as “oriental ethnic drag … a simultaneous performance of the exaggerated mimicry and the frank presentation of the original, such as the performance of an over-feminised drag queen”. Or what the theorist Homi K Bhabha describes as “colonialist mimicry”.

British east Asian actors are forever told to be “more Chinese” (and, occasionally, “more Japanese”). To make their accents stronger. To be more stoic, formal and restrained – ie less human, less relatable and less interesting. In effect, wooden. British east Asian actors of mixed heritage (around half) are excluded early in the TV casting process, despite (or perhaps even because of) our stage pedigree. British east Asian actors are forever told to sound more Chinese to a white gatekeeper’s ears. This results in a bizarre Fu Manchu impersonation that sounds nothing like any Chinese person I’ve ever met in real life.

Bear in mind that Fu Manchu has never, in all his numerous screen appearances, been portrayed by an actor of east Asian heritage. So east Asian actors are effectively imitating the sound made by white actors when they impersonate Chinese people.

This is not opportunity. It is not representation. It is surely not what an actor would spend three years at drama school for. And the idea that if you do it well enough you might get to be like Sandra Oh in Killing Eve is a fallacy. Oh is Canadian but works in the US, a country whose TV industry, while surely not without its own race problems, is a whole eight time-zones away from UK TV’s reductionist racial pigeonholing.

And it’s not representative of the performances that British east Asian actors, with all their diversity and range of backgrounds, have given to great success at the Royal Shakespeare Company and theatres such as the National, Royal Court, Finborough and Arcola.

A change surely has to come. Because otherwise the UK TV industry is simply perpetuating the same racist exclusion that was first pointed out a full 100 years ago.

• British East Asians on Screen and in Television, a free symposium, will be held at City, University of London, on 8 July.