Drivers are being warned it will be illegal to pick up their mobiles during the first test of the Government’s new emergency alert service.
The AA said motorists may prefer to switch off their electronic devices before Sunday’s test as laws banning the use of handheld phones will still apply.
For around 10 seconds from 3pm, millions of smartphones and tablets across the UK will emit a loud alarm and vibrate in a trial of a system that aims to warn the public if there is a danger to life nearby.
They will also display a message about what is happening.
Drivers caught holding a phone behind the wheel face six penalty points and a £200 fine.
AA campaigns manager Lorna Lee said the test is “very welcome” as the system “could be very useful in certain situations”.
She continued: “The test does bring certain risks though, which need to be managed.
“For drivers in particular, awareness of the test is vital to avoid any panic when it sounds.
“If you are driving when the alert sounds, you must not touch your phone to stop the alert as the normal driving laws still apply.
“Instead, wait for a safe place to pull over – not the hard shoulder nor emergency area – acknowledge the alert and continue your journey.
“Some drivers may prefer to switch their phone off in advance if they know they will be driving during the alert test.”
The system is modelled on similar schemes in the US, Canada, the Netherlands and Japan.
The UK’s alerts will initially be used to warn people about severe weather situations including floods and wildfires in their local area.
The Government said on Monday the system could later be used for other forms of emergencies such as terror attacks, nuclear threats and dangerous criminals on the loose.