From today (1 March), motorists found using a handheld phone will get six points on their licence and a £200 fine. The previous punishment was three points and £100 penalty.
Lorry and bus drivers who are found using a phone face being suspended, while new drivers will have their licence revoked if they rack up six or more points within two years of passing their test.
Motorists caught using their phone twice or with 12 points on their licence could be taken to court, banned and fined £1,000.
A seven-day enforcement exercise is now underway; extra patrols are being carried out help police crackdown on drivers using their phones.
About 3,600 drivers were handed penalties in the last co-ordinated enforcement week from 23-29 January, the Department for Transport (DfT) said.
Adverts designed to warn motorists of the new punishments and discourage mobile phone use have been developed, and will be shown at cinemas and on billboards, radio and social media.
The DfT has introduced the tougher penalties after a consultation last year.
The Ministry of Justice's consultation on increasing the maximum sentence for causing death by dangerous driving from 14 years to life in prison closed on 1 February.
Transport secretary Chris Grayling said: "Doubling penalties will act as a strong deterrent to motorists tempted to pick up their phone while driving and will also mean repeat offenders could find themselves banned from our roads if they are caught twice.
"Everyone has a part to play in encouraging their family and friends not to use their phones while driving -- it is as inexcusable as drink driving."