Go hug your children. Hug them right now. This Room review will wait.

Adapted for the screen – from her own novel – by Emma Donoghue, “Room” is a challenging film to watch. Deeply harrowing, nerve shreddingly tense but ultimately richly rewarding; it’s a beautifully realised story of courage, love and resilience.

Ma (Brie Larson) and her young son Jack (Jacob Tremblay) live in ‘Room’. For Jack, Room is the entire world and everything that exists. When Jack reaches his fifth birthday, Ma reveals the horrific truth of their existence: they are prisoners, captives of a man called Old Nick (Sean Bridgers). Determined not to see her son live his life in such conditions, Ma hatches a daring plan to escape and reclaim the life denied to them.

Much of the potency of this complex, disturbing and moving drama comes from the outstandingly powerful performance of Brie Larson, but it’s the astonishing turn by Jacob Tremblay which will linger long in the memory. His intense and intricate performance is breathtakingly accomplished, especially for one so young in their first major role (he previously appeared as Blue in “The Smurfs 2”).

Acclaimed director Lenny Abrahamson (“Frank”) brings the disturbing tale to life with wonderfully innocent camerawork, allowing the viewer the ephemeral yet welcome relative safety of Jack’s naïve world view. There’s sterling support from Joan Allen, William H Macy and Matt Gordon but it’s Larson and Tremblay who keep you mesmerised as they struggle to find their place in the larger world. I can’t speak for fans of the book, but as a film, it’s a triumph of performance and production.