The scene when computer Hal becomes insane in 2001: A Space Odyssey has been named the most important moment in sci-fi history by a panel of experts.
The crew in 2001: A Space Odyssey slowly realise something is wrong
The moment from Stanley Kubrick's 1968 film was chosen by science fiction experts including Thunderbirds creator Gerry Anderson and UFO investigators.
It beat scenes including the chest-bursting sequence from Alien and the final massacre of Blake's Seven.
Six experts were polled for a Sky One programme which was shown on Monday.
2001: A Space Odyssey starred Keir Dullea and Gary Lockwood as astronauts on a mission to Jupiter.
Their ship was operated by the supercomputer Hal 9000, which slowly developed paranoia, leading it to deceive its crew with terrifying effect.
Film-maker Steven Spielberg said: "I think without 2001 there would not have been a Close Encounters or Star Wars.
"2001 was the permission slip that Stanley gave all us students to go out and flex our imaginations."
Actor Mark Hamill, who played Luke Skywalker in three Star Wars films, said: "I don't think they've ever topped that in terms of sheer creepiness of the machines turning against us."
The panel included Professor Martin Smith, a professor of robotics at the University of Central England.
Former UFO Magazine head Tony Dodd, SFX magazine editor Dave Golder and movie broadcaster Kim Newman also took part.
They selected the scene from a shortlist of 30 sci-fi moments from film and television.
The dramatic final episode of Blake's Seven was shortlisted
Other scenes considered included the moment aliens first make contact in Close Encounters of the Third Kind.
The revelation that Darth Vader was Luke Skywalker's father in The Empire Strikes Back also appeared on the shortlist.
Artist Tracy Emin said she was "absolutely delighted" by the sequence.
"That smarmy, sickly, horrible princely-like chap had to be put in his place," she said. "Give me Darth Vader any day."