I definitely don't get to tell a writer what to write or what not to write - and I am a writer too so I understand the balancing act that is required here if you want to slip your political viewpoint into a piece - the trick is to make sure that you're doing so without the audience noticing. Chibnall was particularly bad at this when he did the lecture in Orphan 55.... little short of actually knocking on doors of the audience and telling them what he thought, it was all there front and centre.... very much like a lecture. RTD doesn't do that and that's a blessing.

The Grapes of Wrath is a good example of a writer who already has a loyal audience and a bunch of commercial success - but I'd argue there's a reason why Of Mice and Men is more widely read and better remembered and it comes to the emotional storyline within. By the time he wrote Grapes of Wrath, Steinbeck had earned the right - and anyone who bought it would know (broadly speaking) what they were going to get.

That is also arguably true of RTD too - but there's a difference here and that is the widespread appeal of Dr Who. If you're buying a book by Steinbeck you've directly chosen that work by that author in that style - RTD is inheriting a disparate fan base and he needs to appeal to all of them. The British audience is primarily centre-left, the British theatre is caught up in identity and identity movements where it has been widely rejected outside of a small group of very active viewers. Lots of my friends don't go to the theatre much any more because they got fed up of being lectured at by the writers. That will happen in TV too - and that would be a shame.

So yes, the writer can choose to be a mouthpiece for a political movement and I think RTD's 'Its a Sin' was a masterpiece of that in action. It was beautifully crafted, it was wonderfully political, it was heartbreaking and devastating and beautifully poetic. That was his Grapes of Wrath. I think he needs to be careful with Who, that he tells great stories first and foremost and that any of his more political messages are firmly couched in the needs of the story, not on an ideological Peggy Sue. It would be awful to see TV audiences diminish because of political myopia.

And although we haven't been discussing it, the same applied to Season 4 of Sex Education. 3 series of story led entertainment broadly progressive, followed by a final season which a small vocal group were super keen on - but everyone else thought was 'meh'. It was death by political point over story and it'll come to tarnish the legacy of the show in the long run. :o)