The track, which topped the tally last week after 12 weeks on the chart, fends off competition from LMFAO, who remain at number two with 'Party Rock Anthem', while Christina Perri advances from six to three with 'Jar of Hearts'.
Elsewhere in the Top 10, Katy Perry's 'Last Friday Night (T.G.I.F)' drops from five to six, and Bruno Mars's 'Marry You' leaps from 13 to nine.
Further down the chart, LMFAO and Natalia Kills' 'Champagne Showers' vaults from 26 to 14, and Nicki Minaj's 'Super Bass' jumps from 23 to 18.
Beyoncé's 'Best Thing I Never Had' ascends from 32 to 25, Britney Spears's 'I Wanna Go' lands at 33, and Example's 'Changed The Way You Kissed Me' debuts at 35.
The Top 10 singles in full (click where possible for our reviews):
1. (1) Adele: 'Someone Like You'
2. (2) LMFAO ft. Lauren Bennet & GoonRock: 'Party Rock Anthem'
3. (6) Christina Perri: 'Jar of Hearts'
4. (3) Pitbull ft. Ne-Yo, Afrojack & Nayer: 'Give Me Everything'
5. (4) Adele: 'Rolling In The Deep'
6. (5) Katy Perry: 'Last Friday Night'
7. (7) Jason Derulo: 'Don't Wanna Go Home'
8. (8) DJ Havana Brown: 'We Run The Night'
9. (18) Stan Walker: 'Loud'
10. (9) Marvin Preist: 'Own This Club'
Watch a live performance of Adele's 'Someone Like You' below: