There has been a rich harvest of taut thrillers in 2014, including the independent American features Blue Ruin and Cold In July and gritty British films Locke and Starred Up.
Before I Go To Sleep is guaranteed to jangle nerves and drop a few jaws as summer mellows into autumn.
Following a car accident, 47-year-old Christine Lucas (Nicole Kidman) is diagnosed with anterograde amnesia.
Each morning, she wakes in a bed next to a man she does not know and creeps into the adjacent bathroom where a series of photographs on the wall begin to fill in the blanks.
Then she receives a mysterious telephone call from someone called Dr Nash (Mark Strong), who instructs her to look in the wardrobe .
Before I Go To Sleep drip-feeds us fragmented flashbacks, clouding our judgement of characters as they orbit Christine.
Kidman captures the fragility of a woman at the mercy of her condition.
Firth and Strong offer sterling support and Joffe cranks up the tension masterfully with each hairpin turn.
The guessing game of who to trust is part of the film’s diabolical appeal and the script engineers some wonderful bluffs until a gasp-inducing big reveal that should have audiences teetering precariously on the edge of their seats.