My Old School — the strange tale of a 30-year-old posing as a teenage student

The truth-based fiction film has in recent years been joined by a shadowy counterpart: the untruth-based non-fiction film. Joining the ranks of Capturing the Friedmans, Catfish and The Imposter comes documentary My Old School, the story of a 30-year-old Scotsman who returned to his alma mater in 1993 posing as a 17-year-old orphan.

Bearsden Academy, on the fringes of Glasgow, already seemed out of step with the times, with a headmaster forever clad in long black gown and a deputy who incited pupils to mark her arrival with a borderline-fascistic salute. Into this setting arrived a walking anachronism in old-fashioned blazer and briefcase. He came with a Canadian twang, an exotic back-story — a globetrotting opera singer mother with whom he’d seen the world before her untimely death — and the audacious name Brandon Lee (this only months after the actual Brandon Lee, actor son of Bruce, had been killed on the set of The Crow).

One of the many surprises is that not only was the visibly more mature pupil not shunned by his smart-mouthed Scots schoolmates, he appears to have become something of a social butterfly, befriending bullies and their prey alike, throwing parties, taking his cohorts out clubbing. Teachers were similarly taken, gushing over his knowledge and eloquence, handing out A grades. The final coup de théâtre was the end-of-year production of South Pacific, in which the ostensible introvert took the lead role and wowed the crowds.

Could it be that his ruse went rather too well? What began as a plan with a clear objective — get in, keep a low profile, get out again with good grades — may have been derailed by the seductive glare of popularity, leading the conjuror to overplay his hand. What fascinates most is the question of at what point illusion tipped over into delusion.

Key to this is the testimony of the real man behind the myth, Brian MacKinnon, who now talks to camera but is never seen, his words lip-synced instead by Alan Cumming. The actor gives a slyly chameleonic performance, slipping between bruised vulnerability, smirking creepiness and charismatic bravado. Or is that in fact the magic of MacKinnon, whom we are told had a knack for mesmerism?

This interview footage and those with MacKinnon’s now forty-something classmates are woven together with animated reconstructions of key events, the ginger trickster looking like a young Malcolm McLaren. These cartoon segments not only add jollity, they are perfectly fitting for the Scooby-Doo ending that we know is to come.

Beyond the captivating surface yarn lie deeper layers: insights into the slipperiness of subjectivity and how fact can twist into myth. “He sang like an angel,” recalls one classmate; videotape reveals less than divine vocals. The climactic kiss, which all concerned remember as an affectionless peck, turns out to be something more ambiguous and, in the word of MacKinnon’s young female co-star, “icky”. Yet the overall tone of Jono McLeod’s film is admirably unsensationalist: what could be easy fodder for summary character assassination becomes reflective and, as MacKinnon’s real life story is revealed, flecked with empathy.

It’s a reminder that none of us are exactly what we seem. Who knows what secrets we carry? The FT itself is no stranger to such bizarre antics. It has been alleged that, in the 1950s, Brendan Bracken, one of the paper’s founding fathers and a onetime adviser to Churchill, founded a school (also in Scotland), where he posed as a 16-year-old in flannel shorts in order to be caned by prefects. He was 54.

★★★★☆

In cinemas from August 19