This means you must not use a device in your hand for any reason, whether online or offline. The law applies to you if you’re:
• supervising a learner driver
• stopped at traffic lights
• queuing in traffic
• driving a car that turns the engine off when you stop moving
• holding and using a device that’s offline or in flight mode
There are exceptions, such as if you need to call 999 in an emergency or making a contactless payment in a vehicle that is not moving.
You can find the full rules on using a phone, sat nav or another device when driving on GOV.UK