New drivers now face losing their licence the first time they are caught using a phone behind the wheel illegally.
The penalties and fines handed out to offenders have been doubled to six points and £200 respectively.
The new measures have been introduced in the wake of a number of high-profile cases and research suggesting the practice is widespread.
New drivers can have their licence revoked if they get six penalty points within two years of passing their test, which could now be the result of sending a single text message or making a phone call.
More experienced drivers can lose their licence if they receive 12 points in a three-year period.
The latest figures show 22 people were killed and 99 seriously injured in accidents on Britain’s roads in 2015 where a motorist using a mobile was a contributory factor.
Lorry driver Tomasz Kroker was jailed for 10 years in October after killing a woman and three children after ploughing into their stationary car on the A34 near Newbury, Berkshire, while using his phone.
Transport Secretary Chris Grayling said increasing fixed penalties will be a “strong deterrent” and that using a phone behind the wheel was “as inexcusable as drink driving”.
Members of the public can report repeat offenders anonymously by calling Crimestoppers on 0800 555111.
Police forces are carrying out a seven-day crackdown, with extra patrols and an “increased focus” on catching drivers using mobiles.
Around 3,600 motorists were given penalties during a similar initiative last month.
According to the Transport Research Laboratory, reaction times are twice as long for drivers who are texting compared with those who have been drinking.
A new advert developed by the Government’s road safety group Think! And the AA Charitable Trust shows a drunk man suggesting he should swap places with his sober girlfriend, who is texting on her phone while driving them home.
The campaign will appear at cinemas and on billboards, radio and social media with the message: “You wouldn’t drink and drive. Don’t text and drive.”
AA president Edmund King said too many people are “addicted” to their phones, with half of young drivers unable to bring themselves to turn them off before a journey.
Pete Williams, road safety spokesman at breakdown firm RAC, said encouraging motorists to take personal responsibility for their actions must be at the heart of the campaign to change people’s habits.
Motoring groups say a sharp decline in the number of offenders caught is partly down to police budget cuts affecting enforcement.
An RAC survey found that one in four (26%) motorists admits checking texts, emails and social media while driving.
