In the three years since it became law, it has become one of the most widely - or at least most obviously - flouted pieces of legislation. From today, however, drivers caught using hand-held mobile phones on the move face a doubling of the fine, to £60, and three penalty points on their licence.
There will be a new TV campaign aimed at informing drivers who may claim to have been unaware of the law thus far. And, perhaps more importantly, police forces around the country are planning a seven-day blitz against those spotted yapping away while driving.
According to Meredydd Hughes, the chief constable of South Yorkshire police, 77,000 drivers have been fined for using phones.
And Superintendent Phil O'Kane, of Lothian and Borders police, told BBC News 24: "Simply put, using your mobile phone while driving makes you four times more likely to be involved in an accident. Your reaction time is worse than if you've been drinking alcohol."
He warned that unmarked cars would be used to spot transgressors, and phones could be seized "as evidence".
Users of hands-free equipment were warned that their phones, too, were distracting, and that people involved in a smash while talking could face careless driving charges.
Supt O'Kane went so far as to suggest drivers pull over and stop to talk on the phone. So watch out for the driver in front of you unexpectedly braking as the calls come in.
Curiously, the new law doesn't apply to cyclists, though police could take action for careless or dangerous cycling; just as they could - but rarely do - for riding on the pavement or jumping red lights.
Do let us know if you see police enforcing the new law. Does it go far enough? Should pedestrians be banned from using phones anywhere near a road?
The number of people too wrapped up in their conversations to look before they start to cross the road in London really is scary.
