Elizabeth Is Missing, BBC One (4 stars)

Elizabeth Is Missing, BBC One

Glenda Jackson returns to TV with a powerful story of dementia and intrigue

In possession of the 'triple crown' of acting awards (a Tony, couple of Emmys and a pair of Oscars), Glenda Jackson looks set to scoop more shiny plaudits for her performance in the one-off moving drama Elizabeth Is Missing. Based on the successful debut novel from 2014 by Emma Healey, ex-Labour MP Jackson plays Maud, a woman in the mid-throes of dementia who, in between moments of clarity, is plagued by thoughts and worries about her titular absent friend as well as a possible crime committed against her sister Sukey (Sophie Rundle) when they were both young women in the post-war years.

Armed with a pad of handwritten notes and aided by messages taped to walls, cupboards and doors ('coffee helps memory' 'remember to lock door'), Maud is guided through her foggy life as she begins to forget the identities of the people closest to her. Life in a care home (or 'retirement community' as a New Jersey mobster once insisted on calling it) is clearly looming ever closer.

Written by Andrea Gibb (AfterLife, Dear Frankie), this 90-minute drama might have been a wholly depressing viewing experience were it not for the elements of intrigue injected into it. Maud's dementia might be a calamity for those around her as moods switch from confusion to anger, but she does eventually make enough sense for the two mysteries to be solved by her dogged persistence.

The writing is strong, but Jackson's performance is a tour de force which shows that all the time she spent in the Commons and around her constituency hadn't blunted her acting powers. Jackson's last TV credit was in 1992's The Secret Life of Arnold Bax, directed by Ken Russell (who was behind the camera for the first of her Oscars with Women in Love). If this is ultimately to be her small-screen swansong, she has left behind a masterclass that should be studied for generations to come.

Elizabeth Is Missing airs on BBC One, Sunday 8 December, 9pm.