UNSANE

Cert Running time

Claire Foy suffers a dramatic change of scene in this diverting thriller.

The Brit actress swaps the intense goldfish bowl of royal family life on TV’s The Crown for a stretch as an inmate in a psychiatric asylum.

Well at least I think there’s considerable difference between the two institutions.

Foy is tremendous as a victim of stalking who unwittingly commits herself to observation in a secure facility and is then unable to persuade anyone of her sanity.

An early convert to digital photography, director Steven Soderbergh follows the example of 2015’s arthouse hit Tangerine by shooting Unsane on an iPhone.

And this has a juicy opening as Soderbergh mixes in elements of medical corporate conspiracy from his previous films such as 2013’s Side Effects, but he soon back pedals into well-executed but predictable slasher territory.

His use of wide-angled lenses emphasises Foy’s isolation and anxiety, but this stab at claustrophobic paranoia is never sufficiently barking mad.