The Party, Cillian Murphy's latest flick, is like a night spent on the Titanic just before the iceberg hits.

Something truly alarming is happening to western culture. As the split between the haves and have nots grows, the mediating influence of diversity is getting thoroughly lost.

Put simpler, the knobs no longer have the poors around to tell them when they're off base. It's a disaster for everyone. Case in point is The Party, the new film by director Sally Potter starring Irish actor Cillian Murphy.

Although the film skewers the tone-deaf cultural privilege of the English upper middle class, it does so without reference to any other kind of class experience, neither in pre or post Brexit England, which when you think about it is quite an oversight.

Murphy plays Tom, a rich young man who works in high finance in the city - the city in this case being London - which means among this crowd he's basically a stand in for the devil.

Cillian Murphy as Tom in The Party

Cillian Murphy as Tom in The Party

No sooner does Tom arrive than he reverts to character, snorting cocaine off a shiny bathroom counter to steel himself for the task he's come to perform. That task, it turns out, is to shoot the much older man named Bill (Timothy Spall) who is having an affair with Tom's young wife.

Bill is also the husband of Janet (Kristen Scott Thomas) who is throwing the party. To wit, things are getting pretty complicated fast.

Tom has a vaguely Irish accent but his expensive suit and the gun in his pocket tells us that point is largely irrelevant. Among this lot he's just one more addled voice waiting for the right moment to say what he really thinks.

Janet's has been promoted to the Department of Health,  which becomes increasingly ironic in a bluntly silly way as the night and the party progresses.

Also on board for this ghastly social gathering are some of the cream of European and American film acting, including Patricia Clarkson, Emily Mortimer and Bruno Ganz.

You might think talent of this magnitude could save The Party, but you would be quite wrong. Potter doesn't write characters, she crafts situations and lets her ciphers contend with the riddles she sets them, giving her talented actors little more to do than be rude to each other in an increasingly candid manner.

Janet keeps receiving text messages from an unnamed lover as her unaware husband Bill struggles to come to terms with the fact that his ambitious wife hasn't noticed him in years.

Bill also hasn't noticed that Tom is fixing to shoot him. Perhaps this is because he has already received another death sentence of his own, this one from his docto, who has told him he has incurable cancer and very little time left to live. Under the circumstances you can forgive him for not quite noticing how highly strung the other guests are.

Murphy, a world class actor, looks fantastic as the financial shark on a revenge mission. Inhaling coke to steel himself for the task of murdering one of the party throwers, he's an understandable bag of nerves from the moment he arrives at the front door - and Murphy does well with this underwritten part.

But The Party feels like it might have been rehearsed and filmed minutes later, because the camera work and the pacing feel suited to a TV special or more precisely a play.

You can see what Potter is aiming for; a trenchant criticism of cossetted middle class privileged, one that can only exist within its own self-regarding little bubble, blissfully unaware of the outside world.

But instead of that we get a stilted comedy that's pitched somewhere between high camp and high farce, to what actual end escaped me.

Emily Mortimer and Cherry Jones in The Party

Emily Mortimer and Cherry Jones in The Party

As Martha, the lesbian partner of Jinny (Emily Mortimer), Cherry Jones is given a rough draft of a character and her partner seems to exist only to facilitate risible jokes about conception.

But the scene that saw me finally check out of this interminable flick came when some forgotten vol au vents start to burn up in the kitchen oven. Murphy and Mortimer race to the scene to find the smoke alarm blaring, but they are both unable to press the button to silence it. That's an level of incompetence that turns them into helpless fools, which may be in the script but it undercuts the audiences patience and sympathy.

How much you care about what happens to any of these people largely depends on how much like them you find yourself, I suspect. It's a timely question. More and more, people with the same backgrounds and social classes are being locked into their own little islands of privilege that are never visited by people unlike themselves.

As the people of the UK are slowly discovering, we are no longer sovereign nations or standalone countries now, we are increasingly just massive interconnected Google and Facebook algorithms that have been carefully calculated to show us more and more of what we like and less and less of what we need to know to get by.

If The Party had asked some serious questions about where all this increasing economic exclusivity is leading us it would have been a much more interesting movie. Instead it settles for the kind of cheap dramatic revelations that propel the film but don't really amount to a statement.

There's no question that people this mannered will still bare their fangs when their lives or livelihoods are under threat, but that's not as interesting a question as why they're under threat in the first place.

The Party is where the former radicalism of the aging participants goes to die, clearly. They may have started life with youthful idealism decades earlier, but betrayal will come in the final act, the film assures us.

As messages for our own blighted time go, it's on the money, but it offers the audience and the characters nothing more than a literal circular firing squad. Potter considers The Party a comedy, but considering how divided the post-Brexit UK is now, you may not feel much like laughing.

The Party opens February 16.