The number of Oxfordshire drivers caught illegally using their mobile phones has rocketed, with 17 caught every day.

Last year, 6,363 drivers were sent fixed penalty fine notices by Thames Valley Police – almost double the 2010 tally and up from 1,845 in 2008, the first full year the ban on using a phone was in force.

However the force last night said it had no idea why there had been such an increase.

Just 398 of those motorists last year paid a £60 fine and accepted three penalty points on their licence, with many of the rest going on a £95 awareness course instead.

A road safety charity last night said the “alarming” rise showed punishments are not keeping drivers off their phones, though the force said education was vital.

Brake spokesman Martin Howard said that courses played a crucial role, but added: “Brake wants to see all offending drivers automatically receive points on their licence and a far higher fixed penalty fine.

“This would send a clear message that this behaviour will not be tolerated.”

Force spokesman Alice Adderley said guidance to waive points and a fine for a course was set by the Government and the Association of Chief Police Officers (ACPO).

She said: “It is not possible to give a definitive reason why fines might have gone up or down.

“We want to promote driver education, not enforcement.”

In 2008, 1,845 people were caught and 283 paid the fine.

There were 2,102 caught and 301 fined in 2009 and 3,391 and 337 in 2010. The 2011 figure of 6,363 was the latest total the force had, but does not include the last few days of December, so may rise.

The force could not reveal the number of drivers offered the course at the time of going to press.

James Hargrave, a spokesman for ACPO, said driving experts regard courses as “highly effective in improving long-term driver behaviour on the roads”.

He said: “When compared to fines and licence penalty points, education has a more lasting impact on motorists’ attitudes to driving safely.”

Driving while using a mobile or any device which can send or receive images or messages was banned in February 2007.

This applies to queuing traffic, while use of hands-free kits can lead to police action if an officer believes the driver is not in proper control of their vehicle.

The Highway Code says: “Never use a hand-held microphone when driving.”

Some 220 people appeared in Oxfordshire courts for using a mobile in 2010. These are not included in the police figures.

Of the court cases, six cases were dismissed and 214 were found guilty.

Car drivers face a maximum £1,000 fine and disqualification if their case goes to court.