Celebrity chef Jamie Oliver has banned his children from owning a cell phone to protect them from cyber-bullies. The TV cook worries his children might be subjected to online bullying due to their famous father and does all he can to ensure they are not using social networking websites. Oliver is a close friend of Instagram.com founder Kevin Systrom, and regularly updates his own social networking accounts with posts about his family and businesses, but he was furious when he discovered daughters Poppy, 11, and Daisy, 10, had secretly set up accounts on the photo sharing site. He tells British magazine Closer, "I found out my two eldest girls had set up Instagram accounts in secret, which I was not happy about and soon put a stop to it. Poppy's the only girl in her class still not allowed a mobile. It may sound harsh, but I do worry about the bullying that can go on with these sites. "I know the girls have had a hard time in the past at school because their dad's on TV. I just don't want to risk it happening online too. It's impossible to keep an eye on."