It's not much fun, but sometimes you've got to set some rules for your kids.
"Set specific times when they can access the computer." says Simon. That way you know they're not browsing the whole time, and you can keep a closer eye on what they're up to.
Simon also says you should keep your computer in a family area: "It means you can ensure you are nearby should they access any inappropriate content."
Of course, it's not always easy to get kids to stick to rules. But tell them that breaking the rules will mean they're banned from going on the Internet for a week and we're pretty sure they'll be putty in your hands.