'This Ain't A Love Song' held off competition from Usher and will.i.am's 'OMG', which shot up six spots to number two.
Elsewhere in the chart, Timbaland and Justin Timberlake broke into the top ten, jumping ten places to reach number six with 'Carry Out'.
Meanwhile, Joshua Radin just missed out on the top ten with his single 'I'd Rather Be With You', going straight in at number 11.
However, Delirious? dropped out of the top 40 after an online campaign propelled them to number four last week.
The top ten singles in full (click where possible for our reviews):
1. (1) Scouting For Girls: 'This Ain't A Love Song'
2. (8) Usher ft. will.i.am: 'OMG'
3. (3) Plan B: 'She Said'
4. (2) Lady GaGa ft. Beyoncé: 'Telephone'
5. (5) Tinie Tempah: 'Pass Out'
6. (16) Timbaland ft. Justin Timberlake: 'Carry Out'
7. (9) INNA: 'Hot'
8. (6) Rihanna: 'Rude Boy'
9. (7) Justin Bieber ft. Ludacris: 'Baby'
10. (10) Cheryl Cole: 'Parachute'
Source: Official Charts Company
> Click here for this week's top ten albums