Fleets are being urged by road safety organisations to make company car and van drivers aware of an emergency alert test on their mobile phones to avoid them being distracted.

The siren will sound for 10 seconds on almost every smartphone in the UK on Sunday, April 23, at 3pm.

The alert system will be used to warn of extreme weather events, such as flash floods or wildfires and only when there was an immediate risk to life.

It could also be used during terror incidents or civil defence emergencies if the UK was under attack.

Lucy Straker, campaigns manager at Brake, the road safety charity, told Fleet News: “With the emergency alert test, it is important that people know when it is happening (3pm on Sunday 23 April) so if they have to drive or ride at that time, they are prepared and understand how to respond.

“If your phone is switched on, the alert will play for 10 seconds. If you are driving when the alert occurs, please do not look at or touch your phone until you have safely parked your vehicle and turned off your engine.

“We would also recommend fleet managers inform their drivers of the alert and, if possible, schedule journeys to avoid driving when the alert takes place.”

The test message and alarm is expected to hit 90% of mobile phones in the UK. Phone users can swipe away the alert message or click "OK" on their home screen to continue using their phone as normal.

People who have their phones switched off will not receive the message - but it will sound if your phone is switched to silent.

Rebecca Guy, road safety manager at the Royal Society for the Prevention of Accidents (RoSPA), said: “If the emergency alert system sounds when you are in control of a moving vehicle, resist the urge to look at or pick up your phone and continue driving as normal.

“If you do feel the need to look at your phone, find a safe and legal place to pull over first.”

She added: “While technology is an enabling and helpful tool for road users, we do need to be aware of the distraction risks it can pose.

“We know that in 2021, around 600 people in the UK were injured in road traffic collisions where the driver was using a mobile phone, with the potential for many more being unreported.

“The message here is simple – be aware the alert is coming, and if you are in control of a vehicle when it does, do not pick up your phone.”

The Government has tried to play down concerns that drivers will be distracted by the alerts, potentially leading to accidents, saying evidence from local trials of the alert shows people will wait until they are stationary to check their phones.

Straker said: “We always recommend that people turn off their mobile phone whilst driving or riding – or put it out of reach, in 'Do not disturb/Driving mode' or on silent – so that it is not a distraction.

“We know that any distraction that takes a driver’s mind off the road, for any length of time, is potentially lethal.”

In 2021, mobile phone use contributed to more than 116 fatal or serious collisions on UK roads.