Drivers in the UK could face hefty fines and even a ban for doing one simple thing they might not even realise is illegal.
The change came into force this year, with the Department for Transport announcing that it was looking to make it easier to prosecute drivers who use their phones while on the road.
The new rules are in addition to the existing laws that make it illegal to text or call while behind the wheel - excluding in emergencies.
The law was matched with an update to the Highway Code that made it still count as driving even when the car is stationary, which includes being in traffic apart from very limited circumstances.
What is the one rule that can land you in trouble?
The use of a mobile phone to scroll through songs or play a game in traffic jams and red lights is now illegal.
It will also be illegal to take photos or record videos while behind the wheel - even when stationary.
Satnav and hands-free calls will continue to be allowed, but that is under the condition they remain hands-free. Satnav that is instead picked up by the driver is an offence.
The best way to ensure you use your device hands-free is to secure it in a cradle or stand.
AA president Edmund King said: "By making mobile phone use as socially unacceptable as drink-driving, we are taking big steps to make our roads safer."
The move was introduced after a public consultation found 81% of people supported the change.
How much could you be fined?
Drivers found to be in breach of the rule could be handed a nasty £200 fixed penalty notice.
The sum will come with a huge six-point tariff, which could put many people's licences at risk of being banned.
On top of this, if a driver is found to not be in proper control of their vehicle they could face prosecution - another reminder of why it is vital motorists take proper responsibility for their actions behind the wheel.
Speaking last year about the new laws ahead of their introduction, transport secretary Grant Shapps said: "By making it easier to prosecute people illegally using their phone at the wheel, we are ensuring the law is brought into the 21st Century while further protecting all road users."
The move was backed by the RAC, whose road safety spokesperson Simon Williams said: “As our phones have become more sophisticated, the law has not kept pace and this has allowed some drivers who have been using their handheld phones for purposes other than communicating to exploit a loophole and avoid the maximum penalty.
“While today’s announcement is clearly good news, it’s absolutely vital that the new law is vigorously enforced, otherwise there’s a risk that it won’t deliver the sort of behaviour change that will make our roads safer.”
