Why does my internet cut out when the phone rings?

well, my guess is that you have your internet on your fixed phone line, and that you're not using the dsl technology, but the old settings, what makes your internet line the same one as the phone line, and because you don't have 2 lines, when the phone rings, the internet must be cut because it's dependent of the line that the phone call is currently using, so it's interrupted

If you have DSL, you need a filter on every single device connected to your phone line. That includes answering machines, FAX machines, alarm systems, cordless telephones, and so on. If you have dialup, then it's because your Internet was not configured to block incoming phone calls. You have a choice -- block incoming phone calls and people will get a busy signal when you are online, or don't block them and you will get disconnected from the Internet when people call you.

Without knowing more detail about your setup it is hard to know for sure what could be causing it. If your PC's are wireless and you use cordless phones I'd check to see if they are using the same frequency. 802.11b/g uses 2.4ghz and 802.11a uses 5.8ghz. It appears Sky provides both the phone and internet. If this is the way it is in your case it might be they have something provisioned wrong where a phone call is interrupting your internet. I'm sure you have tried this already but resetting the modem might help since it controls both the internet and phone in a setup like this. Good Luck.