Anyone worried their husband or wife is having an affair can allay or confirm their worst fears with a new smartphone app.

Called mCouple, it enables users to track almost every detail of someone’s life. The app gives access to every phone call, text and email and any activity on Skype and Facebook, as well as pictures and videos taken on a mobile device.

Users can even record their partner’s mobile phone conversations and track their movements using GPS technology. The app was created by London-based firm mSpy, which stressed that users must gain consent before downloading the device on to their partner’s phone.

The company mainly markets it to parents looking to keep tabs on their children or bosses monitoring the behaviour of their staff, but acknowledges that a lot of customers use the technology to try to catch a cheating spouse. Lawyers say that any attempt to spy covertly is strictly illegal.

Slater & Gordon privacy expert Jeremy Clarke-Williams said: ‘As a general rule, if spouses or partners or even bosses hand out mobiles with one of these apps installed, that would seem to be a clear invasion of privacy.’