The most talked about festival film of the year is finally making its way to UK cinemas, and it exceeds even the highest of expectations.

Known for his English-language films Snowpiercer and Okja, prolific Korean director Bong Joon-ho returns to his native language for the tasteful and tense Parasite. Bong’s long-time collaborator Song Kang-ho plays Ki-taek, the father of the poverty-stricken Kim family whose desire to climb the social ladder has the most disastrous of consequences. While the entire ensemble is outstanding, Song’s performance is what anchors the audience throughout.

Courtesy of IMDb

A tragedy that plays out in two distinct halves, the arc is a precisely plotted rise and fall, where everyone gets what’s coming to them, and nobody is let off the hook. The Kim family gain employment at the house of the wealthy and gullible Park family, tutoring their children, driving their car and washing their clothes, and the question at is heart is, of course, who the real parasite is. The Kims weaponise dishonesty to infiltrate the Parks’ home and get paid more than they’re really owed, but the Parks literally live off the Kims’ labour.

There is no simple black-and-white morality here – the complacent rich and the grasping poor each have their sympathetic moments and their monstrous ones. The real vitriol here is focussed on the system itself that entrenches these differences.

Bong is a master of symbolism, with physical levels of the city and of the house making tangible the class divide – a brilliantly effective sequence sees the Kims running back to their basement home from the Parks’ house, descending down and down through winding levels of the city through the pouring rain that’s flooded their home entirely, but was only a minor inconvenience to the Parks. It’s beautifully simple, and perfectly executed.

Rising stars Park So-dam and Choi Woo-sik have a brilliant rapport as the quick-thinking Kim siblings, who so easily wrap the naïve and nervous Mrs Park (Jo Yeo-jeong) around their little fingers, while Mrs Kim (Jang Hye-jin)’s rivalry with the old housekeeper Moon-gwang (Lee Jeong-eun) leads to some of the best comedy-action in the film as well as the most nail-biting tension.

There is a sharp sense of humour throughout, under which lurks what is close to a horror film, and the two in such close conjunction keeps the audience guessing until the very end, never quite sure what genre conventions to expect. That’s the glory of Parasite – with power dynamics on a pendulum swing, moments of shocking violence have an intense impact that might be lost elsewhere, simply because they’re so unexpected. But everything is perfectly planned – the incredibly precise design of the Parks’ stunning house allows for brilliant shots that always reveal something else going on in the background – a beautiful veneer, with deep horror lurking beneath.

Parasite is in cinemas from 7 February.