Seven of the most memorable interlopers in cinema

1. Tom Ripley, various films

Created by novelist Patricia Highsmith, sociopathic social climber Tom Ripley has had many faces in the cinema – Alain Delon (Plein Soleil, 1960), Dennis Hopper (The American Friend, 1977), Matt Damon (The Talented Mr Ripley, 1999), John Malkovich (Ripley’s Game, 2002), Barry Pepper (Ripley Under Ground, 2005). All offer smooth, plausible surface charm with lizardiness behind the eyes.

It's appropriate that Ripley has seldom been the same man twice since his identity is so mutable. To him, other people are skins to be worn or dolls to be broken or things in the way which need to shift.

Highsmith and the filmmakers always try to give equal time and weight to whichever outclassed dimwit is Ripley's latest pet project… but they tend not to survive, whereas Ripley does, becoming by default the hero in his own story.

2. Priape Boudu, Boudu Saved From Drowning

Shambling, hairy tramp Boudu – played by character actor Michel Simon, once hailed ‘the ugliest man in the world’, in Jean Renoir's 1932 black comedy – attempts suicide by jumping off a bridge into the Seine. Bourgeois Lestingois (Charles Granval) rescues him and feels obliged to invite him into his household and spruce him up. However, the anarchic sensualist won’t be tamed and instead pulls Lestingois’ family apart, inspiring servants and children to rebel and even seducing Madame L.

Adapted from a play by René Fauchois, Boudu Saved From Drowning is the ur-text of many a disruptive houseguest drama. Simon was aptly replaced by later badly behaved primal presences in remakes – Nick Nolte in Down and Out in Beverly Hills (1986) and Gerard Depardieu in Boudu (2005)

3. Sheridan Whiteside, The Man Who Came to Dinner

The hit 1939 play by Moss Hart and George S Kaufman – filmed with original star Monty Woolley in 1942 – was an in-joke at the expense of the writers' New York intelligentsia pal, acerbic theatre critic Alexander Woollcott, who was said to be the worst imaginable guest.

A big city egomaniac celebrity is invited to dine with a well-to-do-but-ordinary small town family but trips on an icy front doorstep and breaks his hip and is confined to the Stanley house for months, inviting a parade of bizarre eccentrics (including Jimmy Durante as ‘Banjo’ – a takeoff on Harpo Marx) to visit and sniffing out the scandal that an old Stanley aunt is really a once-famous axe murderess.

4. Hugo Barrett, The Servant

Boudu and Whitside are disruptors whose comical transgressions expose hypocrisies. Over the decades, screen interlopers follow Ripley and become more sinister figures. In Joseph Losey's 1963 film, scripted by Harold Pinter from a novel by Robin Maugham, louche, wealthy young man (James Fox) comes to rely on his deferential valet Hugo (Dirk Bogarde) so much that the white-gloved, soft-spoken servant takes over his London house.

The exchange of positions between Fox and Bogarde would often be repeated in movies. Fox was an interloper himself in Nicolas Roeg and Donald Cammell's Performance where a gangster barges into the mansion of a pop star (Mick Jagger) and the opposites meld, while meek cuckoo-in-the-nest Sissy Spacek steals Shelley Duvall's whole identity in Robert Altman's 3 Women.

5. John Ryder, The Hitcher

“My mother told me never to do this,” says young driver Jim (C Thomas Howell) as he picks up hitch-hiker Ryder (Rutger Hauer). He needs someone to talk to stay awake on a cross-country drive.

Ryder's conversational gambits – “you wanna how what happens to an eyeball when it gets punctured?” – certainly prevent sleep, but Robert Harmon's ruthless, relentless road psycho movie from 1986 is an illustration of what happens when you unwittingly invite a monster into that most personal of spaces, your car.

6. Hedra Carlson, Single White Female

Jennifer Jason Leigh, an incidental victim in The Hitcher, became an interloper herself in this 1992 entry in the female-psycho-from-hell sub-genre of the '80s and '90s (see Fatal Attraction, The Hand That Rocks the Cradle and Poison Ivy).

New Yorker Allie Jones (Bridget Fonda) needs a flatmate and advertises for a ‘single white female’ (which was evidently legal then). She gets mousy Hedra, who transforms into a clone of Allie, adopting her clothes style and hairdo and experimenting early with digital identity theft.

7. Oliver Quick, Saltburn

Now we've considered the history of interloping, it's worth noting that Oliver from 2023's streaming monster hit Saltburn isn't just a 21st century Ripley. He owes something to Boudu and Hugo – not to mention Michael York in Something for Everyone, Terence Stamp in Teorema and even Ingrid Pitt in Hammer's The Vampire Lovers (as Mark Kermode points out, “he does drink blood”).

As played so memorably by Barry Keoghan in Emerald Fennell's film, as he worms his way into a wealthy household, he also seduces and/or kills family members and hangers-on to emerge as ruler of the roost.

To discover more about what makes cinematic interlopers so compelling, listen to the episode in full on BBC Sounds.