'Block'em' a new anti-bullying application is being launched to stop cyber bullying among children through their mobile phones.
Helen Perry, who was herself subjected to harassing phone calls through her mobile, and friend Stephen Anderson developed the app.
The app blocks phone calls and texts from specified numbers so that the owner of the phone can still keep their original number and the person making the nuisance calls or texts does not know they are being blocked.
"I found it all very unpleasant as an adult and I couldn't stop looking at the messages," Perry told Sky News Online.
"Then I started to imagine what it would be like for a child to experience it," she added.
Priced at 1.79 pounds, the app can be downloaded from the 'Block'em' website and is aimed at children between the age of 11 and 15 with 70 percent of the profits from the sale going back to children's charity NSPCC.