It should last about 20 seconds and will be confirmed in the alert that it is a test and no further action is needed.
Emergency alerts are an important way of reaching people quickly in an emergency. The emergency alert system has been used 5 times since its first national test. We are being asked to use the alert to think about how we can prepare for an emergency and to use the Prepare website for more information.
It is important that people know to expect the emergency alert test so they are not panicked.
However the alert may particularly cause concern for anyone who has a concealed phone in the case of domestic abuse which would receive the alert. In these circumstances it's possible to opt out.