"Conclave".

If you thought Oxford University's recent election of a new Chancellor was a badly-run, drawn-out affair full of backbiting and skullduggery, well, just be grateful it wasn't a new Pope. If Conclave is to be believed, what those cardinals get up to would horrify even Peter Mandelson.

Edward Berger's adaptation of Robert Harris's Vatican intrigue novel is a tense, twisty political thriller with one foot in 12 Angry Men and the other in The Da Vinci Code. The Pope is dead, and 108 naughty, squabbling, Catholic leaders assemble in Rome under the world-weary eye of Ralph Fiennes' Cardinal Lawrence, to decide, in the time-honoured fashion of forming secret alliances rather than holding a democratic debate, who should be the next Supreme Pontiff.

The paper they burn to tell folks outside how far they've got in their decision-making is either black or white. But really it should be blue, because the process ignites an unholy ecclesiastical fireworks display of epic proportions.

The movie influence that really stamps its stylistic branding-iron on Conclave's backside is László Nemes' harrowing 2015 Holocaust drama Son of Saul. As in that film, the camera clings to our central character like a limpet, seeing events unfold from his point of view. Instead of Auschwitz he stomps around the Vatican. It may be less deadly, but it still resembles a prison compound, especially since the cardinals are sequestered for the entire film, unable to leave or communicate with the outside world. 

Fiennes embarks on a series of meetings with the key Papal candidates, all of them played by leading actors of our day: Lucian Msmati, Stanley Tucci, John Lithgow. Isabella Rossellini threatens to upstage the lot of them as Sister Agnes, the only character with an unblemished moral compass. In fact, after a while it becomes quite hard to figure out if they are fighting over who is going to be Pope or who is going to win the Best Supporting Actor Oscar. Both processes are very similar.

But if anyone from Conclave does get to be High Priest of Hollywood next spring, it must surely be Fiennes. For all the fun and the scheming, he brings a depth of human responsibility and, yes, spirituality to his role which make the endless close-ups function like character studies for a Renaissance portrait. His eyes aren't just dark wells; they're dark wells with stagnant water at the bottom, gradually receding into lifeless despair.

Although the Vatican itself refused permission for filming (and given the reputational pummelling this film gives the Catholic Church one can't really blame them) the locations used in Conclave are all Rome-based, and it has a fantastic sense of place. Cardinals natter and smoke while leaning against 2000-year-old marble statues, and their monastic cells manage to be just about ascetic enough while still affording ample luxury. If you ignore the slightly over-the-top Agatha Christieness of the plot, it almost feels like peeking on the real thing.

Ultimately the papal election boils down to a choice between a 'progressive' candidate who believes in gay rights and women priests, and a 'traditional' candidate who wants to get rid of all the Muslims. In a US election year the metaphorical significance is only too obvious, and at one level Conclave works as a delicious political satire of contemporary extremism in America and the wider world.

Like every good whodunnit, or in this case whowillgeddit, there's a twist at the end - in fact a double twist. To be fair, you can see at least part of it coming a mile off, and it's so contrived and unconvincing that it actually does a disservice to the rest of the film, which brings subtle shades of grey to this red and black story.

Robert Harris is the master of placing thrillers into convincing, historical contexts. Conclave does that with aplomb. If it leaves a slight aftertaste of silliness, like Monty Python's Spanish Inquisition sketch (if it had a proper budget), I say let's enjoy it. After all, this isn't a serious piece of work like 12 Angry Men. It's 108 Angry Cardinals Trying Not to Elect Donald Trump. And that's entertainment.