It is marketed as the perfect solution for worried mothers and vigilant bosses: secret mobile phone spyware that monitors a person's texts, calls, photos, emails and web browsing.

''I can now keep an eye on my babies - even when I'm at work!'' reads a testimonial for one spyware product.

''Now that we know the truth, our profits are up by more than 10%!'' another happy customer reports.

Yet new technologies such as GPS trackers and mobile phone spyware are increasingly being used to stalk, harass and threaten women in a new form of domestic abuse that legal experts say is highly disturbing.

MobiStealth, the product that received such rave reviews online, was used by convicted murderer Simon Gittany to read his girlfriend Lisa Harnum's text messages, one of several forms of control and surveillance he subjected her to.