Rob Carnevale verdict: two stars

Dir: Leigh Whannell

With: Lin Shaye, Stefanie Scott, Dermot Mulroney

Running time: 97mins

The law of diminishing returns bedevils this latest entry into the Insidious franchise, a once enjoyable but now horrifically generic exercise in scare-mongering. Opting for a prequel approach, Leigh Whannell's film shows how gifted psychic Elise Rainer (Lin Shaye, reprising her role from the first two instalments) reluctantly agrees to help a teenage girl (Stefanie Scott) who has unwittingly summoned a demon while attempting to contact the ghost of her late mother. Aside from the odd jump, however, this third film becomes an increasingly tedious and nonsensical plod through dark corridors and rooms that not only reworks genre convention but also repeats itself endlessly. A late appearance from Whannell (also reprising his role as a comic relief ghost hunter) does at least bring some humour - but it's all too fleeting and more than a little half-hearted. For too long, Insidious: Chapter 3 feels like the franchise cash-in it really is.