Picnic at Hanging Rock review – Australian fever dream still dazzling 50 years on

Peter Weir’s eerie and lugubrious mystery chiller from 1975, adapted by screenwriter Cliff Green from the novel by Joan Lindsay, is now rereleased for its 50th anniversary. It’s a supernatural parable of imperial anxiety and sexual hysteria: the bizarre and unclassifiable story of three demure and porcelain-white schoolgirls and one teacher who on Valentine’s Day 1900 – with the 19th century over and the Victorian age less than a year to run – simply vanish in the burning sun while on a picnic excursion to the forbiddingly vast monolith Hanging Rock in southern Australia. No one here uses the Indigenous name Ngannelong and the only Indigenous character is a tracker.

They disappear while exploring its rugged forms and inlets, which weirdly resemble the faces of Easter Island statues. Like the Marabar Caves in Forster’s A Passage to India, Hanging Rock is the centre of some unknowable enigma, almost audibly humming or throbbing with insects, a phenomenon that resists being subdued by the outsider’s rational law.

The film is a classic of the Australian new wave and, in its sun-stricken hallucinatory strangeness, one to put alongside Ted Kotcheff’s Wake in Fright or Nic Roeg’s Walkabout from 1971; it is a movie that influenced much later Australian films such as Greg McLean’s Wolf Creek and Ray Lawrence’s Jindabyne. It fascinatingly affects the mannerism of a true-crime cold case, but it is not based on anything from real life; author Joan Lindsay said it came to her in a dream. (A new biography of Lindsay points out that this great novel was not published until she was 71, after a lifetime of feeling marginalised and erased as a creative artist – another possible explanation for the vanishing.)

Perhaps bizarrely, the obvious real-world point of reference occurred after both novel and film: the press paranoia surrounding the Chamberlain baby case in 1980, in which a two-month-old disappeared without trace while the family was on a camping holiday near the awe-inspiringly gigantic rock Uluru, and where the police and courts disbelieved the mother’s (finally vindicated) claim that a dingo had taken her baby. (It was the subject of Fred Schepisi’s film Evil Angels – AKA A Cry in the Dark – in 1988, with Meryl Streep.)

Related: ‘Clambering about in Victorian boots was brutal’: how we made Picnic at Hanging Rock

Rachel Roberts plays English headteacher Mrs Appleyard, a widow who is privately plagued by memories of summer holidays with her late husband in Bournemouth. She has permitted certain girls to go on a picnic to Hanging Rock, while those who have displeased her must stay on the school grounds. These dreamily sweet teenagers, longing for romance and love and nursing crushes on each other, are like the vestal virgins of some votive cult: the cult of Saint Valentine, in fact. There is something almost hypnotised in their behaviour, as if they know what is to happen, that they are to be secret sacrifices to a hidden god or be returned to their planet of origin.

When the catastrophe is revealed, it convulses the school and the surrounding townships, disclosing a suppressed misery and fear, and simple exhaustion. Is it that the girls in their diaphanous white dresses represent the most vulnerable side of an effete colonial people, who are destined to evaporate in the heat and dust? Or that they represent a willed romantic self-immolation in the face of repression – a striking part of the case is that one missing girl is recovered, without her corsets. The film’s mystery still shimmers.

• Picnic at Hanging Rock is in UK and Irish cinemas from 21 February, and in Australian cinemas from 14 April.