Ridley Scott's long-awaited return to science fiction pulls in more than £6 million over the Jubilee weekend to easily secure the top spot. Snow White, which opened last Monday, pulls in £3.5 million from its 473 nationwide locations.
Last week's chart-topper Men in Black 3 falls down to number three, while Avengers Assemble slips to number four. Joss Whedon's superhero ensemble has now earned £48 million from its UK theatrical run.
Sacha Baron Cohen's latest comedy The Dictator completes the top five.
Elsewhere, the top ten sees new entries from Top Cat: The Movie and The Angels' Share at numbers seven and nine respectively.
The UK box office top ten in full:
1. (-) Prometheus - £6,236,580
2. (-) Snow White and the Huntsman - £3,589,027
3. (1) Men in Black 3 - £3,032,053
4. (3) Avengers Assemble - £847,598
5. (2) The Dictator - £754,068
6. (4) What to Expect When You're Expecting - £633,935
7. (-) Top Cat: The Movie - £457,287
8. (6) American Pie: Reunion - £267,682
9. (-) The Angels' Share - £256,446
10. (7) Moonrise Kingdom - £210,804
Watch Digital Spy's Prometheus interview with Michael Fassbender: