Using a hand-held phone while driving became illegal in December

Since the law banning mobiles was introduced in December, police have been issuing warnings to drivers rather than fining them.

But Thames Valley Police are advising people that this warning period has now ended and drivers caught using a hand-held phone will be fined �30.

If drivers are taken to court they could face a fine of up to �1,000 to �2,500 for commercial drivers.

No call is so important that you should risk your life for it Superintendent Neil Olney

Superintendent Neil Olney, head of the Thames Valley Roads Policing department, said: "Drivers have had two months of leniency but now we will be enforcing this law more rigorously and will be setting up road-side checks to make sure drivers are observing the law.

"You are four times more likely to crash if you are using a mobile phone.

"Our advice to drivers is to switch off your mobile phone when you are in the car or divert calls to voicemail.

"No call is so important that you should risk your life for it."