For the uninitiated, this film could be incredibly disturbing. For those used to dark films, it goes further than most.

The first thing to note is that Possession does some very unusual things. Before anything supernatural happens, the actors begin behaving incredibly strangely. At first, it seems like they are overacting. For a brief moment, you could be forgiven for thinking you are watching a bad film.

You should know better.

The standout performance is Isabelle Adjani. She is hypnotic, deranged, pitiable and seductive, sometimes all at once.

Sam Neill is great, as always.

These actors know what they are doing.

Under the direction of Andrzej Żutawski, the cast are signposting wrongness. Later, you may wish you had taken heed.

By the time you realise you are watching one of the most disturbing sequences ever committed to film, it is too late to back out.

You have been warned.