First things first, and a quick line the producers of POSH can use in any publicity should they wish to … ‘topical, relevant, well-written, well-cast, well-acted and very thought-provoking.’ As to what I really think about it, even a good night’s sleep has not settled the answer.

Perhaps that is the sign of a good play, that it gets you thinking in a way you didn’t expect it to. Or perhaps I am thinking about it too much because I knew before going last night that on Thursday I will be chairing a debate about the play and what it says about class in Britain today, so I need to get my thinking clear before then.

I am sticking to my commitment to do the debate even though an hour after I made it I was given the tempting rival offer of a seat on BBC Question Time’s panel on the day David Cameron appears before the Leveson Inquiry. I was sorely tempted to tell POSH to bog off, but a promise is a promise and all that.

We will however be discussing some of the same things, as it is hard to imagine POSH would be doing so well in the West End were it not for the fact that David Cameron, George Osborne and Boris Johnson are in positions of power, and that they were once members of the kind of debauched, right-wing, upper-class Oxford University dining club portrayed in the play.

Most of us did some pretty silly things in our youth. The question is whether the kind of attitudes on display continue to form a part of the worldview of those now governing Britain. That Cameron understands the political risks of that are clear enough. Why else was a good deal of time, effort and money devoted to taking a picture of him and his pals in their Bullingdon Club uniform out of circulation? And why did he put so much effort into playing down his background, and playing up the idea of himself as a fairly ordinary middle-class kind of guy, in his ultimately unsuccessful effort to win a majority?

One of the most intriguing things last night was the reaction of the audience. Some laughed a lot. Some – myself included – laughed rarely. Almost from the off, I found the characters so repellent that I found it hard to accept anything they said or did should be rewarded with appreciation. At times it was more like watching a horror film than a satire, the horror all the more intense because of the sense that people like this really do still exist, really do think money can buy them out of any problem, really do have connections, influence and, in some cases, power.

Yet what was also interesting, despite all the bravado and the arrogance, was how vulnerable they felt. They had to lie about the nature of the dinner. Deep down they sense most people find them ridiculous. And they hate having to pretend that people lower down the social order have any real value whatsoever compared with their own sense of their own merit. One of the most irritating characters early on – annoyingly called Alistair – becomes one of the most interesting as he seeks to give political shape and sense to who they are and why they behave as they do. I won’t give any of the plot away but his little speeches are among the most powerful parts of the play.

POSH was first performed at the much cheaper Royal Court Jerwood Theatre. Seemingly they got less laughter there, and more of a political response from the audience. I sensed yesterday a divide between those who felt a certain sympathy with the very right-wing worldview driving through the play, and those who felt troubled at the ‘them and us’ nature of where power lies, that for people like them to get power, they have to pretend to be people like us, but that ultimately the reality of their upbringing runs too deep for them ever to understand the lives of most people. That is why Tory MP Nadine Dorries’ description of Cameron and Osborne as ‘two arrogant posh boys who don ‘t know the price of milk’ is so potent.

It is also why the PM and the Chancellor will not be terribly pleased to hear that having started with the Royal Court, and now made it at the Duke of York’s, the next step for POSH is the big screen. Governments breed their own culture and their own fertile ground for satirists. Fair to say that a lot of ours came in so-called spin – think Feelgood, The Thick of It, Rory Bremner. For all their efforts to declass the issue of class, for the Tories, that may be the area where popular culture’s take on them lands, with an impact they are probably right to feel uneasy about.

Below is a link to the event I am chairing at the theatre on Thursday, before the performance. Rachel Johnson, editor of The Lady, is confirmed as a panellist. According to her tweets, she left the play before the end. I assume that means she was either very annoyed by it – I did sense that George Balfour was a kind of cross between her brother Boris and Cameron – or even more troubled than I was. I look forward to finding out. I also hope the writer or producer will be there.