If this app is installed on your phone you wouldn't know it. And that's what makes it so scary.

Jealous? Paranoid? Obsessed with the idea that your partner is going to cheat on you?

There’s an app for that.

In fact, there’s quite a few.

An app made in Brazil called Boyfriend Tracker,  which tracked the phone user’s movements, was removed from Google Play last year after a public outcry over invasion of privacy. But stalker apps are like the many-headed Hydra: cut off one head, and two more will grow in its place.

Now there’s an app called mCouple, which can be installed secretly on your partner’s phone and doesn’t show up in their app lists. It can track everything from Facebook messages to GPS coordinates. And then there’s mSpy, software that monitors “calls, text messages, locations, of anyone, anywhere, 24 hours a day”.

Interestingly, the Internet – useful a forum full of bad advice – doesn’t seem to think stalker apps are a very good idea.

Lindy West wrote for Jezebel, “Human beings, we really, really, really need to get over this shit. Spending all of your time obsessing over your partner’s movements, assuming the worst about them every time they leave the house, and flying into jealous rages if they speak to any people who are not you, is not a mentally healthy (or fun) way to exist.”

One relationship commentator told Fox News, “If you feel inclined to do something like this for your girlfriend, boyfriend, husband, wife – you’re probably with the wrong partner if you’re that suspicious.”

And an investigations operations manager pointed out to Ninemsn that, “people were committing an offence if they secretly monitored their partner’s phone with invasive software.”

Despite the fact that stalking your spouse is almost universally considered to be a terrible idea, there’s clearly a market for such software. The question is, who’s buying it?

While it would be easy to write off the entirety of this market as jealous, insecure partners – the reality is that this technology is capable of so much more.

Think about it.

This technology can be used to monitor who someone is contacting. When they are contacting them. Where they are going. The regularity with which they visit certain places.

Yes, these apps have been designed to help jealous spouses discover if their partner is cheating. But it can be used by anyone. It can be used by partners who want to control and monitor who their lover talks to, and where they go throughout the day.

In other words, these apps are tools that facilitate emotional abuse.

What is particularly troubling about the information that the apps can provide to the abuser – whether a man or a woman – is that victims sometimes cannot leave an emotionally or physically abusive relationship without help.

They might need a place to stay. They might need financial support. They will almost certainly need emotional support.

Sometimes the decision to leave takes a long time to come to. A lot of planning – or a lot of talking oneself into it, and out of it, and into it again.

Apps like these allow the abuser to track their partner’s conversations, and intervene before they are able to leave. Or wait until they have left, and follow them to a new location that was supposed to be their safe space.

Apps that allow you to stalk your partner are, in any circumstance, obviously a gross invasion of privacy and a breach of trust.

But this technology can be downloaded and used by anyone. There’s no mental health check. There is no way to tell whether the individual installing the software is harmless, or capable of inflicting a great deal of hurt.

It’s available to anyone who will pay for it.

Jealous ex-girlfriends and emotional abusers alike.

Do you think these apps need to be more closely regulated, given the purposes they can be used for?