this is actually your iPhone checking for email etc but because wifi goes to sleep it uses 3G hence the message.
source: the o2 website.
solution: turn off 3G when your not using it or disable push email.
- 'Windows 9' LEAK: Microsoft's playing catchup with Linux
- Game Theory Half a BILLION in the making: Bungie's Destiny reviewed
- Review A SCORCHIO fatboy SSD: Samsung SSD850 PRO 3D V-NAND
- Was Earth once covered in HELLFIRE? No – more like a wet Sunday night in Iceland
- Every billionaire needs a PANZER TANK, right? STOP THERE, Paul Allen