iPhone owners who find themselves in a dangerous situation could save their own lives with a handy hidden trick.
Those with iOS 11 have the ability to quickly call the police by pressing the lock button, located on the side of the phone, five times.
An 'emergency SOS' slider will appear on the screen. If the phone's owner swipes right on it, it automatically calls emergency services in a quicker and more discreet way than simply dialling 111.
This function will also automatically alert the iPhone's emergency contacts, sending them the phone's current location as well as updates if said location changes.
If the iPhone's location services were turned off at the time of the SOS call, they will temporarily be turned back on.
Many people were unaware of the safety feature and were alerted to it by Twitter user @crueldra, who posted a screenshot of the emergency SOS feature.
However her claim that local police would be sent a 'ping' with a GPS location, resulting in an officer being automatically dispatched, was false, as it only sends the GPS location to those in the emergency contacts list.
Pressing the lock button five times to access the emergency SOS only applies to those with an iPhone 7 or an earlier model, as long as it has iOS 11 installed.
Those with an iPhone X, 8 or 8 Plus need to press and hold the lock button as well as one of the volume buttons until the SOS slider appears.
Some users also took issue with @crueldra's use of the term 'ladies', claiming that her tweet excluded men who are also at risk of being attacked or assaulted.