Police caught 72 drivers using mobile phones illegally on South Yorkshire's roads the month after tougher punishments were introduced.
Nationally, more than 200 drivers a day were caught between March 1 and 28, with 2.5 a day spotted by South Yorkshire police officers.
Campaigners claim the 'worrying' findings suggest many drivers are ignoring repeated warnings about the dangers of using phones at the wheel despite a string of publicity campaigns and the risk of harsher sanctions.
From March 1, those falling foul of the rules have faced receiving six points on their licence and a £200 fine - up from the previous penalty of three points and £100.
The changes mean new drivers risk losing their licence for sending a single text.
Figures obtained following Freedom of Information requests show forces recorded 5,977 instances of the practice the four weeks after the clampdown was rolled out alongside a nationwide police campaign.
The actual figure is likely to be higher as seven forces did not provide figures.
The Metropolitan Police registered the highest number at 2,037, meaning more than 70 drivers were caught using a handheld phone on London's roads each day.
The RAC Foundation described the increased penalties as 'a start', but warned the figures for March suggest 'the key message still isn't sinking in'.
Steve Gooding, director of the motoring research charity, said: "Driving is a safety-critical activity that requires our full attention. Hands need to be on the wheel and eyes looking out of the windscreen, not down at the phone screen."
Brake spokesman Jack Kushner described the number of drivers 'selfishly using their mobile phones behind the wheel' as concerning.
"Driver distraction is a growing menace and it's worrying that drivers don't seem to be getting the message," he said.
The road safety charity wants the £200 fine to be 'significantly increased' to deter offenders.
Twenty-two 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, Department for Transport figures show.
Police say they want to make using a mobile while driving as 'socially unacceptable' as drink-driving.