I watched it through to the end today. I know there are various takes on it, so here is mine.
I thought it was a brilliant, passionate play about England and its neglected people; people who made only a few fleeting appearances in the drama but were the deciding vote.
It was, by the same token, an equally passionate play about those who exploited them. That aspect of the play was played as savage caricature, as an exploitation of misery made possible by contemporary technology. In that respect it was a play whose heart was clearly on the Remain side.
The important point about the neglected was that they were neither patronised nor demonised in the writing. They were presented not as a rabid racist mob but as people who felt an understandable anger and suspicion regarding those they deemed to be responsible for their condition, an anger and suspicion that could easily be converted into racism and xenophobia for the purposes of the vote, though this was something the Cummings character only understood at the very end.
Some people think the play was too short to explore the whole phenomenon but I don't agree. It was the compression that turned a potentially sprawling exposition it into drama, and - as I read it -tragedy.
The focus group was a little over-stereotypical and not wholly convincing but it served a dramatic purpose in the woman's breakdown. The Tories featured were mostly caricature of course, but they too had a necessary part in the form.
Tragedy has been defined as the downfall of a flawed hero. Cummings - as written by Graham and played by Cumberbatch - was a kind of autistic genius with a genuine perception of the way reality stacked up, but who - being entirely obsessed with his vision - had no regard for what his perception might lead to.
In other words, Cumberbatch-Cummings had both the furious intellectual energy, the defiance of convention necessary to drive and dominate the action. That, in itself, is enough to make him a dramatic hero.
The flaw was obvious throughout but held back until it could be displayed at the climax.